Here are some cheats and tips for the game Sky Kid.
SXEKGZVI Infinite lives
PANYNZLA Start with 1 life–both players
TANYNZLA Start with 6 lives–both players
PANYNZLE Start with 9 lives–both players
VANNVZSA Player 1 has more lives than player 2
AAOKIZPA Shoot more bullets
IAVNNZPA + GAVNUZAA Start at level 5
ZAVNNZPE + PAVNUZAE Start at level 10
APVNNZPA + YAVNUZAE Start at level 15
GPVNNZPA + LPVNUZAA Start at level 20