Balls in Space; I mean, not that playing any Flash game is very "safe for work", but Balls in Space isn't NSFW in that way, if you know what I mean (hint hint, nudge nudge, say no more!).
Now that we've got that out of the way, let me tell you about the game: You're a ball. On your own, you can run and jump, and that's about it. But as with good platformers, power-ups abound. Specifically, you collect little balls along the way which you can shoot out at the baddies. The balls don't go in a straight line - they're subject to gravity, and they bounce off walls and barriers.
Another handy power-up is the Ninja, which lets you execute double-jumps. With these (and perhaps a couple of others which I have yet to uncover) you basically need go through the levels, kill the baddies, and get to the door every time. A few minutes into the game you'll find a nice homage to the Mario franchise, too. Quite a fun little game!