You pilot your purple jelly craft in a classic sidscrolling space shooter, destroying enemy crafts and scenery as well as picking up weapon power-ups and extra lives.

Free to play the first several levels; $10 shareware after that.

From the developer's site:

description
Take the role of a purple alien thing that kind of looks like a squid and pilot your way towards Earth in a quest to destroy mankind. Causing lots of destruction along the way is of course a way to make the trip less dull. You pilot your purple jelly craft in a classic sidscrolling space shooter, destroying enemy crafts and scenery as well as picking up weapon power-ups and extra lives along the way.
features
- Smooth scaling, transparencies and anti-aliased sprites
- 16 side-scrolling arcade space shooter levels
- Multi-channel stereo panning sound
- Four weapon systems each with four upgrade levels and a special attack
- Lots of explosions and particles
- Original Mp3 music soundtrack
- Really unexpected ending

requirements
MacOS X
QuickTime
OpenGL Hardware