Enter name as icheat.
All Weapons: A, Right, c-Down, c-right, c-up, A, left
Weapons power up: Down, Up (2),Z(2),left, right
Mutant alien: c-down, up, Z (2),c-right while facing harvester it will
turn into an mutant alien.
Surreal: down, up, right (3), A, left
Fat legged alien: left, A, right, down
Difficulty cheat:
To get very easy levels repeatedly hit left,
To get very hard levels repeatedly hit right.