This bundle includes:
- Beat Hazard Ultra
- Dynamite Jack
- Solar 2
- Night Sky HD
And for those who pay more than the average:
- Super Hexagon
- Dungeon Defenders (And all the DLC)
Keep in mind you can only get Dungeon Defenders on PC.
Remember that if you pay more than the average you get the bonus games, anything they may add to the bundle later, and all of those games' soundtracks.
Source - HumbleBundle.com