Glasshouse 

3D puzzles with a gravity gun

Glasshouse is a puzzle game that will remind some of the highly rated Portal. Instead of that games portal creating gun, in Glasshouse you have a gravity gun that can attract or repel objects.

Developed by a university team, this a surprisingly polished game. The opening sequence is great, and a little eerie. During the first few levels, you're introduced to the game's controls and mechanics. While tutorials are a really good idea, we felt this was a little slow. Once they are over, the game gets harder, and you're charged with executing well timed jumps around platforms, where failure results in instant death!

Moving objects around with the gun is effective, and while it takes a bit of getting used to, you'll soon be happily placing, or throwing, objects where you want them. It's pretty tricky, and dying can be quite irritating, but it's only 20 levels, and never gets boring. Aside from being tricky, some people might find Glasshouse a bit pretentious (it has literary level names) and the experience feels a bit lonely!

Glasshouse is an interesting puzzle game, and is absolutely fantastic quality for a free game.