In Metroid, shooting an unfrozen enemy froze it and shooting a frozen enemy damaged it (and unfroze it). This is also how it currently works in SMBC. In later Metroid games, shooting an unfrozen enemy both froze and damaged it, but could not kill it (it would stay alive with 1 HP). Shooting a frozen enemy would damage and potentially kill it (and not unfreeze it). Perhaps Classic Samus should use the classic Ice Beam behavior, and Modern Samus should use the modern behavior? (Obviously this would apply to Pit as well).