VVVVVV
There are a few rooms that really tested my patience, and made me curse the slightly-floaty controls. The game sometimes demands a level of precision that slippery movement can make intensely difficult. But it's hard to stay mad at VVVVVV, because you never lose more than a few seconds of progress.
Despite its brevity - I finished in about two hours of gameplay - there is even a little diversity to the experience. Each of the game's six (depending how you count them) levels has its own game-altering gimmick; and to find the levels, you'll need to explore the space around your ship, in what somewhat resembles a Metroid-styled overworld. The collectible trinkets add a little extra flavor, along with some unlockable modes, although for my part I think pursuing these would be more frustration than it's worth.
VVVVVV doesn't reach the divine heights of Braid or show you as diverse environs as a Super Mario. But it's a unique and impressive platform game that'll get your mind going, and is relatively easy to digest. Also, the music is awesome.
If you're at all frugal - and don't get me started about being frugal - $15 for a two-hour game will strike you a little roughly. In a marketplace where hours-long games tend under $10, VVVVVV really isn't priced competitively. But try looking at it another way: that's just more than a good lunch, or a movie ticket. This is fun, for $15. Who cares! Do it.
Better than: most Flash games
Not as good as: Braid
Ideal price point: $5, I'd think
Progress: 12 trinkets, 865 deaths