Other game editors comparable to KS editor?

Ok, now I have really been bitten by the game-editing bug. So, do you know about other editors that are similar in complexity to editors on this site? I mean for other games...

Ya, I'm really interested in this as well.

I've seen "Atmosphir" - a 3D platformer that is similar. However, it is not nearly as flexible as KS. Many levels end up looking the same.

I've heard people mention "Game Maker"...Anyone have any thoughts?

Making a mod for The Underside would probably be at a similar level.

Making a mod for The Underside would probably be at a similar level.

I second. Slightly more advanced, a good step up from KS

I've heard people mention "Game Maker"...Anyone have any thoughts?

GameMaker (which i use) is for developing games from scratch, not editing them. If you are into game dev, it's great, but for simple editing, it's way to complex.