112th Seed is a cute little puzzle game. It's fun, short, and an easy 1000 gamerscore.
You play as the 112th seed, a geneticly modified plant to survive in a polluted world. You'll need to travel through a series of tests to prove yourself and free scientists. The story doesn't make much sense and doesn't take much time. There's a few cutscenes you can skip through.
The main gameplay is in small 2D test rooms. The seed can push blocks or drops of water, and he can plant himself to create a platform. However, the game gets harder, as drops of water are needed to plant the seed, and the drops don't survive a long fall. You'll need to plan carefully to advance. Later in the game, you'll gain the ability to transform into a flying plant. Fortunately, guides exist for any levels you find too hard. I had to use a guide twice.
Each level is only about a minute long, which is the perfect length for this game. To get all the achievements, you'll need to beat 30 levels and nothing else. The actual game goes on for more than 70 levels, if you enjoy it.