Vortex

Unlimited lives:
Enter JTTSJ as a password.

Unlimited ammunition:
Enter WSVTQ as a password.

Invincibility:
Enter HVZSM as a password.

Level select:
Enter CTGXF as a password. Press Up or Down to select a new starting level.

Hint: Level 3 short-cut:
If you start as the walker on the asteroid level, level 3, turn and face northeast towards the second bend of the asteroids on the map. Walk forward quickly and jump at the last second. Once reaching the maximum jump height, turn into the sonic jet. Energy will be quickly lost, but there is enough to get you to the second corner of the asteroids. An energy refill is at this location. This is the best way to get through this level, because it is timed and very difficult to navigate through quickly.