Pro Action Replay Codes:
?? Is The Number of Lemmings On Bar (At Bottom of Screen) - 00DB5B:?? -Rune
Infinite Time One's Digit - 00DAD3:09 -Rune
Infinite Time Ten's Digit - 00DAD2:09 -Rune
Infinite Time Minutes' Digit - 00DAD1:09 -Rune
Infinite Climber - 00DB72:0A -Datel
Infinite Floater - 00DB73:0A -Datel
Infinite Bomber - 00DB74:0A -Datel
Infinite Blocker - 00DB75:0A -Datel
Infinite Builder - 00DB76:0A -Datel
Infinite Basher - 00DB77:0A -Datel
Infinite Miner - 00DB78:0A -Datel
Infinite Digger - 00DB79:0A -Datel
Always Have 100% Lemmings Saved - 00DB4C:64 -Datel
Level Select [Note 1] - 00DB9D:?? -Datel
Note 1: Switch Action Replay off during play so you can go to the next level!

Game Genie Codes:
Infinite use of all types of lemmings - 00D-34D-19E -Galoob
Infinite time--turn codes off to complete level - 009-FFF-3BE -Galoob
1 lemming equals 100 - 3E8-57C-082 + 3E8-59C-805 + 648-5AC-E64 -Galoob