Toribash
Could you go a little more in depth as to what is going wrong exactly? Otherwise we will end up blindly looking around to look for something which will take longer than you looking for it yourself.
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There's a 50% chance that it's your computer spec's creating issues, I'm not an artist nor do I have gimp, but I have installed gimp before and used it for a short amount of time. It has a pretty ''large'' download and most likely has a large amount of content in the folder and it's possible it can't handle your pc's specs. Windows 8 computers sucks, imo.

If not installing an older version works than its probably your computer's specs creating the problem.
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<[T]Oblivion> roland im ur biggest fan
I agree that Windows 8 Computers suck, but I am also using 8.1 and have not had any such problems with GIMP. All I can say is to check your specs and redownload it, then check that it has installed properly.
I'm a game developer for other games.
Ping me if you have a query or general question unrelated to this game.
I have 8.1
It crashes while loading. Doesn't go into the main screen.
I redownloaded it, but for now, I'm using adobe photoshop elements 6
It might be to do with the Fonts Cache. Here is a forum link which describes multiple methods used to fix GIMP load-crash errors. This is more or less the 'last resort' in terms of this problem if it is not specs and not installation problems.
(The Fonts Cache causes 60% of crashes in GIMP in newer versions)
I'm a game developer for other games.
Ping me if you have a query or general question unrelated to this game.