Cheat Codes

All codes are done on the splash screen:

R, L, A, A, A, B, Up, Left, Down, Right, Up, A

Effect: Alien Ships in Tactical Database

---

Up, Down, A, B, Left, Right, L, L, R, R, B, A

Effect: Invincibility

---

Up, Up, L, R, Down, Down, A, A, B, A

Effect: Mission Select