In no particular order:
- Windosill - a quirky little puzzle/adventure game from Vectorpark. Only has about 10-15 minutes of gameplay in it, but it's very entertaining and cost less than 3 Euros. Highly recommended, even if you're not an adventure games fan.
- Osmos - ambient, atmospheric and fairly challenging abstract puzzle game from Hemisphere Games. Starts out easy but the difficulty ramp up fast! Surprisingly addicting, I came back to this game more often than I thought I would after getting stuck on some particularly hard level and not touching it for a couple weeks at a time.
- Eschalon - this game actually came out in 2007, but I played it in 2009 and its sequel is due in about two weeks from Basilisk Games. An old-school isometric RPG- similar to Baldur's Gate, Fallout, Arcanum and co but shorter and smaller in scale than the classics. A lot of fun if you're a classic RPG aficionado like myself, and there are not many good alternatives if you are looking for games in that genre today.
- DoomRL - not new, but extensively updated in the past few months with a nice bunch of new master traits, special weapons, armors and items. If you are looking for a modern action-oriented roguelike I don't think you will find anything better than Kornel Kisielewicz's DoomRL. Plus, you can't beat the price ;)
- Small Worlds - David Shute's atmospheric "zen platformer" - short and sweet. A true work of art, and if not for its very modest length I would have considered a worthy challenger to Knytt Stories as the best game of its kind. This one is also free.
- Minecraft - a charming voxel-based building game still under heavy development by Markus Persson, quite possibly the most talented game developer I've had the pleasure to meet. It's hard to explain what minecraft is all about, but luckily you can try it out for free in your browser. Cooperatively build elaborate structures by placing single building blocks in a persistent online world (or in my case, destroy said structures by removing blocks and get kicked off the server).
- Machinarium - beautifully drawn point-and-click adventure game from Amanita Design. Not exactly my favorite genre, but I've still had a lot of fun with this little game. The puzzles can get a bit frustrating at times, but if you get stuck you can get hints by playing a short horizontal shooter mini-game(!)
- Star Guard - a highly stylized retro jump-and-run platformer by Loren Schmidt. It's not a very large game, nor is it very sophisticated, but it's pretty, very well made and tells its story in a fairly innovative way. Play it in hard mode if you want an authentic early 80's experience.