Here are some cheats and tips for the game Gradius.
SXOOYYVI Both players have infinite lives
AENELZLA Both players start with 1 life
IENELZLA Both players start with 6 lives
AENELZLE Both players start with 9 lives
KOXOLYSP Keep power capsules
NNOEKPIE Increase force field protection
YGUONUZS + YGKPUUIL Never lose weapons