There are three versions of the Cat Planet game in this folder:
2009 Jam Version
2010 Bugfix Version
2017 Rerelease
Here is an explanation of the version differences. 

Cat Planet was made for the Ludum Dare 16 game jam. The "2009 Jam Version" is the original submission to the jam, and is the most buggy version of the game. It is only of historical interest.

The "2010 Bugfix Version" fixes some bugs, but not as many as the "2017 Rerelease". It is probably the version that most people played, since it was available for longer than any other versions. It is included for nostalgia purposes.

The "2017 Rerelease" is the recommended version. It has the fewest bugs, it changes one line of dialogue, and it updates the credits sequence to say "sylvie" instead of my old internet alias.