Stage 1

SXKOZPVG        Infinite grenades
SZSPYAVG        Start with double capacity magazine
AEKESYGE        Double hits
SXKAUYVT        Don't take damage

Stage 2

GAKEAPIA        Start on stage 2
SZVAXTVT        Don't take damage

Stage 3

LAEGGATA        Start on stage 3

Stage 4

SXKEUZVG        Freeze timer
IEVEOPLA        Play with more time
PAKOIPIE        Double hits
ZAKOIPIA        Halve hits
GEXEUPTE        Start with double ammo