2024 Aug 25: version 2.3.0 (by Michael Hansen (Zrax), ChosenID, David Stolp (pieguy),
A Sickly Silver Moon, G lander, and Eevee)
* Tile World is now built with Qt5 or 6 instead of 4, and with SDL2 instead of 1.
* Level author info is additionally read from DAT field 9, if available.
* On macOS, the main window now regains focus after closing dialogs.
* Repository now contains CCLPs 1 through 5 with documentation.
* Pedantic Lynx emulates Block Kicking.
* Batch verify no longer segfaults, and allows verifying solutions for
different sets.
* MS logic now emulates many previously MS-only glitches.

2017 Jul 12: version 2.2.0 (by Eric Schmidt)
* Display levelsets and ruleset toggle instead of .dac files;
  automatically generate "missing" .dac files.
* Menu option to copy best times to clipboard.
* Menu option to toggle showing the timer on untimed levels.
* During solution playback, press D to display the stepping and initial
* random force floor direction.
* Allow more keys to work when game is paused.
* Allow seeking to work even before solution playback starts.
* During solution playback, press E to advance a tick and Shift-E to advance
  a move.
* New Help->About menu option.
* New Help->Keys menu option.
* The data directory is now a search directory for files referenced by .ccx
  files. This allows including images in level prologues and epilogues, using
  the <img> tag.

2015 Dec 26: version 2.1.1 (by Eric Schmidt)
* The game no longer crashes when starting with a set specified on the
  commandline or when only a single set is available.
* Implemented all the changes to the MS and Lynx logic listed under the
  Changelog for versions 1.3.1 and and 1.3.2 that were not already
  implemented.
* (Lynx logic) Chip can no longer change direction when stuck inside a
  teleport. This change also prevents Chip's location wrongly being considered
  adjacent to the teleport.
* In Lynx pedantic mode, creatures can interact with various things they start
  on. This includes creatures on popup walls causing walls to appear under
  Chip. It does not include the correct behavior for teleports or for Chip on
  a clone machine.
* In Lynx pedantic mode, Chip starting on ice is stuck, and blocks starting
  on ice do not move automatically.

2014 Mar 26: version 2.1.0 (by Eric Schmidt, with contributions from
             Madhav Shanbhag)
* Main window layout changed; in particular, passwords are visible.
* Fixed Lynx toggle wall bug: if a level stopped running the instant a
  toggle button was pressed, the walls would toggle the next time play
  started.
* When selecting a level set, the game now tries to start on the level the
  player left off from, rather than the earliest unsolved level.
* MS mouse emulation bug fixed. (report and fix from David Stolp)
* Some "stuck key" problems fixed, such as Alt-Tab on Windows 7.
* The fileio.c patch, which fixes a .tws corruption problem on 64-bit Linux,
  has been applied.
* Added the ability to disable the display of CCX text when visiting or
  completing a level.
* Added ability to view CCX text via menu options.
* Messages displayed when winning, dying, or running out of time are now
  customizable via external file.
* When playback of the solution to the last level in the set finishes, the
  congratulatory message box wouldn't appear. Now it does.
* In Lynx mode, it is now possible to select the starting direction for the
  "random" force floors, by using the "f" key.
* Added settings file. There are currently two settings: (i) whether to
  display CCX text, and (ii) sound volume.
* Debug/cheat keys completely disabled for releases.
* In pedantic Lynx mode, when an entity attempts to leave the map, rather
  than play being halted, a warning is printed on stderr, and play
  continues as in non-pedantic mode.
* "Goto" menu item renamed "Enter Password", and greyed out during play.
  (Before, it could be selected, but it would not do anything.)
* Miscellaneous code changes not visible to users, to eliminate compiler
  warnings and for other reasons.

2010 Dec 22: version 2.0.0 (by Madhav Shanbhag)
* First public release of Tile World 2 featuring numerous improvements.

2006 Apr 17: version 1.3.0
* Added mouse handling to the code. That includes modifying the SDL code to
  handle mouse activity, adding a large set of new commands, making it
  possible for Chip to move towards a goal over several ticks, and
  modifying the action struct (and the solution file) to permit storing the
  new moves in solutions.
* Added the database of unsolvable levels, which warns users before they
  play a level known to be unsolvable, and automatically gives them the
  password to the next level.
* Added the solution file display, allowing the user to manage multiple
  solution files for a single level set.
* Changed code to accept a solution file as the sole cmdline argument, if
  the solution file contains the set name. Hopefully this, and the previous
  addition, will make it easier for people to share solution files.
* Added the batch-mode verification feature, to check the existing
  solutions without initializing the GUI subsystem.
* Fixed the old emulation bug (MS logic) involving Chip turning a cloned
  block into a clone of himself while going through a teleport.
* Fixed the bug (MS logic) preventing Chip from pushing a slipping block
  parallel to its slipping direction when the push happens through a
  teleport.
* Improved the emulation of several creatures teleporting simultaneously
  (Lynx logic), with assistance from ccexplore.
* Minor improvements to the Lynx pedantic mode.
* Fixed the password input routine. (It was completely broken; not sure
  when that happened.)
* Rewrote the code so that level data and solutions are kept compressed in
  memory, and expanded only when needed, instead of decoding entire files
  when read. This change makes for a small reduction in memory usage, and
  reduces the overall level of useless work being done.
* Added code to shutter the map view when MS gameplay is paused.
* Numerous minor tweaks to the code, the display, and the documentation.

2006 Feb 24: version 1.2.2
* Finally got the handling of brown buttons (MS logic) working correctly.
  It's been a long time coming, and it's all so simple in hindsight.
* Added code to grok the new solution file format. This version of Tile
  World will continue to use the old solution file format, but if it
  encounters a file in the new format, it will handle it correctly.
* Added the ability to specify a solution file by name on the command-line.
* Added -P option for Lynx pedantic mode.
* Added the Shift-Ctrl-X feature to permanently delete solutions.
* Fixed bugs in Shift-Tab feature, and formally documented this feature.
* Fixed bug in the stepping UI.
* Fixed bug reported by Thomas Harte, where an international keyboard
  generating a non-Latin-1 character could cause TW to segfault.
* Fixed bug reported by Catatonic Porpoise, where SDL was being asked to
  blit to a locked surface.
* Fixed a segfault in MS logic reported by Evan Dummit (occurring when a
  cloner's creature in the northwest corner is replaced by Chip).
* Added casts to avoid new warnings in gcc 4.
* Fixed a few other minor MS emulation bugs reported by Evan Dummit.
* Added a number of unfixed MS emulation bugs to msbugs.txt, several of
  which were reported by Evan Dummit.
* A handful of documentation errors were also found and fixed.

2004 Oct 21: version 1.2.1
* Introduced a basic stepping-control UI, and added stepping information to
  the solution file format.
* Fixed a bug (MS logic) reported by David Stolp, involving blocks going
  out and back into the slip list so quickly that they weren't sent to the
  end of the list.
* Fixed a bug (MS logic) reported by David Stolp where block and creatures
  were not moving into key tiles if the bottom tile prevented it (e.g. a
  wall).
* Fixed a bug in sdltext.c, reported by Dale Bryan caused a segfault in
  16-bit color mode.
* Added -r (read-only) cmdline option.

2004 Oct 04: version 1.2.0
* Fixed a bug (MS logic) preventing cloned tanks from turning around when
  they hadn't yet left the clone machine.
* Fixed another longstanding bug (MS logic) involving a tank indirectly
  pushing a blue button. Again, the bug was fixed explicitly instead of
  trying to make the behavior arise naturally from the code.
* Improved some of the behavior of blocks being pushed (Lynx logic).
* Improved some of the behavior of blocked teleports (Lynx logic).
* Altered animations to run for either 11 or 12 frames, depending on the
  parity of their initial frame, as discovered by ccexplore. (This finally
  killed the nine-lived clone-boosting bug in ICEHOUSE!) Also modified the
  point during the frame when animations get removed.
* Changed the Lynx walker to use a PRNG equivalent to the original, as
  worked out by ccexplore.
* Fixed bug (MS logic) in how a block is removed from the slip list when
  being pushed by Chip (reported by Shmuel Siegel).
* Fixed bug (MS logic) with deferred button presses; TW was incorrectly
  deferring Chip's button presses and not just those caused by block
  pushing.
* Fixed a horrid bug when encountering bogus values in a dat file. (The
  code was meant to gracefully ignore the broken level and continue reading
  the next level, but it failed to move the file position out of the broken
  level before doing so.)
* Fixed keyboard routines so that they now understand characters as well as
  keystrokes (thus e.g. the program recognizes "?" when entered on a
  European keyboard).
* Added a help screen for the initial file menu.
* A few other minor bug fixes and miscellaneous improvements.

2003 Mar 15: version 1.1.3
* Put the display code through another significant rewrite. This time, the
  rewrite seems to have succeeded in improving speeds, at all pixel depths.
  Instead of hand-rolled arrays and functions, the new code uses SDL
  surfaces and blits throughout. Tiles are stored in the screen's pixel
  format whenever possible, and alpha channels are used to handle
  transparency.
* Fixed longstanding bug (MS logic) involving Chip pushing a block off of
  another block via a teleport. (Wasn't hard to fix -- just required some
  nose-holding.)
* Added new fractional time display (using -t) for MS. It's still
  imperfect, but it doesn't hurt to make the feature available.
* Added -f switch to get fullscreen mode (change requested by Philippe
  Brochard).

2003 Mar 08: version 1.1.2
* Added frame-skipping code, so that gameplay doesn't slow down on slower
  hardware.
* Blocks on beartraps were getting default initial direction of nil (Lynx
  logic). Default changed to north. (Reported by ccexplore.)
* Fixed broken handling (Lynx logic) of creatures that start out on ice
  (reported by ccexplore).
* Fixed bug where tanks could be turned around while sliding (Lynx logic).
* It is now possible to finish a level with exactly zero seconds left (Lynx
  logic).
* Improved fixlynx feature to also fix the maps for levels 121 and 127.
* Reorganized logic code to use fewer static variables.

2003 Mar 01: version 1.1.1
* Fixed broken handling (MS logic) of tanks not stopping in traps, and the
  fact that tanks on clone machines can sometimes turn around (reported by
  ccexplore).
* Attempted to fix controller bug, where a controller being added to the
  slip list sets the controller direction according to its slipping
  direction rather than its visible direction (reported by ccexplore).
  Hopefully fixing this hasn't broken anything else.

2003 Feb 22: version 1.1
* Fixed most of the broken handling of controllers (MS logic).
* Added guards against bad data in encoded maps.
* Added -a cmdline switch to help improve sound.
* Removed unintentional trigraphs from source.
* Added missing initialization of PRNGs.
* New images for the chip and the socket -- and, finally, a real icon
  (courtesy of Anders Kaseorg).
* Upgraded the Windows copy of SDL to 1.2.5a.

2002 May 06: version 1.0

* Added "(paused)" message when game is paused.
* Minor bugfix in behavior when the creature count maxes out (Lynx).
* Added intro-ms.dat and intro-lynx.dat.
* Fleshed out the README file.
* First official release to the general public.

2002 Apr 06: version 0.10.6

* Fixed off-by-one timing bug (MS logic) when last move of a level is
  involuntary (discovered by Anders Kaseorg).
* Changed pause button to work as a toggle (i.e., no other keys will exit
  pause mode), as requested by Hallgeir Flø.

2002 Feb 25: version 0.10.5

* Amended the Lynx ruleset to follow the button-wiring lists in the dat
  file, instead of using the original Lynx method of implicit wiring.
* Fixed uninitialized variable in password-entry function (reported by
  Ruben Spaans).
* Fixed moving-block behavior so that they will always enter a square that
  Chip occupies, regardless of what Chip is standing on (MS).
* Fixed force-floor behavior so that Chip gets to make a voluntary move
  immediately after stepping on a force floor if his forced move failed.
  (Hopefully this is an accurate coverage of the case that TW was getting
  wrong, and only of that.)

2002 Feb 04: version 0.10.4

* Separated out the two kinds of splashes.
* Fixed changing level by password (broken in 0.10.3; reported by Hallgeir
  Flø).
* Fixed a couple of bugs in handling invalid levels under Lynx (reported by
  Chuck Sommerville).
* Fixed several minor bugs (including several reported by Anders Kaseorg).
* Began a final code cleanup pass. Improved the comments in most of the
  source.
* More documentation changes, including a new README.

2002 Jan 28: version 0.10.3

* Added "Melinda" feature.
* Reformatted documentation, so man and html versions come from a single
  source.

2002 Jan 20: version 0.10.2

* Auto-deprecate saved games that are broken.
* Added some more protection against Ctrl-Ms in text files.
* Fix for die-if-no-soundcard bug (reported by Bill Darrah).
* Added resources entries for changing the color scheme.
* Added hackish "fixlynx" keyword.
* New: first draft of some real documentation.

2002 Jan 13: version 0.10.1

* Fixed the bug in the lynx emulation where Chip survived when he
  shouldn't, using a gross little hack. I hate it. But I've been sitting on
  this bug for over a month now. It's time to give up and put it out of its
  misery.
* Fixed the Lynx clock (it was off by one).
* Added a simple end-screen to display when the player finishes the last
  level of a set.
* Added a little more error-checking in the map decoding.
* Added some basic documentation.

2002 Jan 03: version 0.10.0

* Vastly improved the Lynx emulation of "diagonal" moves. Had to change the
  save file format (again!!) so that diagonal moves could be properly
  stored.
* Added a volume control.
* Fixed bug in Lynx logic that prevented Chip from standing still on the
  very first frame when starting on a force floor.
* Fixes for a few other random things.

2002 Jan 01: version 0.9.3

* Added a proper Chip-dies sequence to the Lynx emulation. Also removed
  redundant "dirt splash" sequence.
* A rough attempt at handling "diagonal" moves in Lynx emulation has been
  put in place.

2001 Dec 27: version 0.9.2

* A couple more memory leaks fixed (these inside of SDL).
* New tile bitmap format, which permits the use of animated tiles.
* A couple of stupid crashes that slipped into the previous version have
  been repaired.
* Miscellaneous other tweaks.

2001 Dec 07: version 0.9.1

* Added the ability to return to the initial file display. At last!
* Full-scale assault on the code to weed out memory leaks. (In my defense,
  the majority of them technically weren't leaks before the prior change
  was implemented.)
* Added -t option (unfortunately it's not as useful as I'd hoped it would
  be).
* Fixed segfault when trying to play back solution on an unsolved level.
* Improved the onomatopoeia display.
* Reorganized the online help.

2001 Dec 03: version 0.9.0

* Found and fixed the obscure slide delay bug that was causing the
  discrepancy in Eric Schmidt's level 29 ("PARAMECIA")!
* Threw out all the text-drawing code and replaced it with routines that
  deal in proportional fonts. Which naturally necessitated rewriting a
  bunch of the code that displayed text. Lots of changes. Created an
  abstract table "object", so that my tables could be realized either on
  the text console or in a proportional font equally well.
* Implemented sound! Spent an entire weekend making 25 wave files -- and
  they still sound ridiculous. (But the fact that the game finally has
  sound is nice.) Onomatopoeia is still available via a cmdline switch.
* Added password-checking code, plus functions to allow the user to jump to
  a level by entering a password.
* Changed the save file format (again!) to store password information, and
  to be a little smaller.
* Added the configuration file feature, with a few configuration options.
  This necessitated adding yet another directory, and once again moving the
  old one.
* Various bug fixes that I've forgotten about while working on all the
  other things.

2001 Nov 14: version 0.8.4

* Rewrote a lot of the display code to avoid redundant drawing of areas of
  the screen. Didn't really make it faster, but I did make it more to my
  liking. Also rewrote all of the text display code.
* Removed gamestate data that was only needed by one of the logic modules
  and made it private to that module.
* Fixed bug found by Mike L. regarding the ordering of clones (MS).
* Fixed bug regarding Chip trying to move on random force floors (MS).
* Added code to indicate when Chip is pushing (Lynx).

2001 Nov 10: version 0.8.3

* MS logic bug fix (clone machine would get stuck if clone died while
  exiting).
* Mixed improvement of display code. (The really cool revamping of the
  display code wound out performing horribly on 24-bit displays, and so had
  to be tossed out.)

2001 Nov 08: version 0.8.2

* Found problem with teleports (MS): creatures provide their own teleport
  blockage! Fixed.
* Careful investigation revealed more timing bugs with buttons, teleports,
  and maybe beartraps as well (MS). Rewrote the endmovement() function
  until everything was being done in the right order.
* Added an "rc" file which can be edited to change the filenames of the
  external resources.
* Discovered and fixed a discrepancy in the slide delay (MS).
* The usual sundry tweaks.

2001 Oct 29: version 0.8.1

* Fixed bug introduced in 0.7.2, correctly this time.
* Fixed intermittent memory corruption caused by an uninitialized stack
  variable.

2001 Oct 28: version 0.8.0

* Fixed bug introduced in 0.7.2 which caused Chip to "come to rest" when he
  couldn't make a forced move (MS).
* Fixed buried beartrap behavior in MS game logic.
* Altered the solution file format (been wanting to do that for a long
  time).
* Gave the program an icon (a temporary one, until I can get someone to
  make me a real icon).

2001 Oct 23: version 0.7.2

* Fixed two bugs in MS game logic discovered by Anders Kaseorg (creatures
  entering random slide floors, and Chip causing slide delay).
* Rewrote the clone machine code to better match the internals of the MS
  game (thanks to recent discoveries). Also fixed the red-button logic so
  that clones do not block their own clone machines.

2001 Oct 22: version 0.7.1

* Fixed bug in MS game logic found by Anders Kaseorg (button not recognized
  when hit by a block being pushed by Chip while on the slip list).

2001 Oct 21: version 0.7.0

* Altered handling of the slip list in the MS game logic. Creatures on the
  slip list now have their slip direction stored separately from their
  pointed direction, and the former is determined at the time they enter a
  tile, instead of just before moving off of it.
* My first serious attempt at implementing slide delay!
* Many little tweaks to the MS logic. I think it's getting close....
* The tile images are no longer compiled into the binary; instead they are
  loaded out of an external bitmap file. The rendering code was changed to
  use 32-bit images internally instead of 8-bit images, so that all types
  of bitmaps can be accepted.
* Added a new shared subdirectory for holding the data files; the main
  shared directory is now used to hold images.
* Altered the onomatopoeia code to ease future introduction of sound.
* Fixed the Lynx bug regarding the bequeathing of a slide token, or rather
  the lack thereof, when Chip is at a force-floor dead end.

2001 Oct 05: version 0.6.0

* Rewrote several fundamentals of the MS game logic, in order to bring it
  more in line with MS's layered map, as well as its treatment of blocks as
  non-creatures.
* Made some general changes to the game internals in order to accommodate
  the above changes.
* Many tweaks and improvements to the MS game logic.
* Added the Ctrl-X feature to permit replacement of saved games --
  something I should have added a long time ago.

2001 Aug 27: version 0.5.1

* Made some changes in the game-saving code to avoid an infinite loop that
  was sometimes happening under Windows.
* Fixed two bugs in MS game logic identified by Anders Kaseorg. (1. Chip
  can only attempt to move once per tick -- a failed move still counts. 2.
  Creatures moving onto the slide list make their first slide move in the
  same tick.)

2001 Aug 19: version 0.5

* First alpha version.
* The SVGAlib layer has been replaced with a much more complete layer for
  SDL. The program can now be compiled for either X or MS Windows. (All
  hail SDL and gcc's cross-compiling capabilities!) SDL also works under
  SVGAlib, but it looks terrible on my hardware.
* A version of the game logic implementing the MS ruleset (with lots of
  bugs) has been added. The program can now switch between the two
  rulesets.
* I ripped the entire code base apart and put it back together again
  (except for the parts that were thrown out). The code is somewhat better
  organized now.
* Code was added to select data files, display scores, and lots of little
  things all over the place.
* Comments! They're still pretty skeletal, but they're better than what was
  there before.

2001 Jul 15: version 0.1

* The previous game logic has been replaced with a complete game logic
  module for the Lynx ruleset.
* The SVGAlib layer has been heavily rewritten to do raw keyboard polling
  and smooth-scrolling.
* Lots of other changes and bug fixes.

2001 May 19: version 0.0

* First limited public release.
* Most of the basic infrastructure is in place, including a working draft
  of a game logic module.
