Alienzix

Key features
- Cooperative mode for 2 players at one computer
- 4 difficulty levels
- 26 levels in 6 sections
- 30 weapons
- Weapon evolutions. If you take the same weapon twice, it evolves into a more powerful one.
- Illustrated manual in HTML format with tables.Game
Descending bonuses give you weapons, lives, shield etc.

The goal of every level is to destroy all the objects that shoot at the player. Obviously you need to evade their shots and use the Hyper-Gravitation in a pinch. Also don't collide with the flying enemies.

In 2-player mode you gain 50% less energy, so that the game isn't too easy. Second player gets less damage, but is also slower. When you get bonus X, the first player gets 50 energy units, while the second one doesn't, but the bonus explosion is more powerful than usual.