You pay what you want (yes you read right). But if you pay more than the average, which is $4.84 at the moment, you'll get 4 games in addition.
No matter what you pay, you'll get Stealth Bastard Deluxe, which is awesome!
Also Fractal and Pulse to be mentioned. All titles except Pulse, which is Android only, are cross-platform and runs on Android, OSX, Windows and GNU/Linux.
I play them on Linux and must say, they are awesome, running perfectly. Aquaria is a big game, with wonderful graphics. McPixel is the opposite, but a whole lot fun. Hilarous 8-bit style game.
For Android, your device needs some juice. So if you have an older device, you might not be able to play all of these games perfectly.
5 days left. For me it was a sure deal.