Toadforce

Toadforce casts you as a bio-mechanical battle toad sent on a perilous mission: a distant planet holds the central computer of an advanced defense system, and you must destroy it. Armed with a jetpack and laser, you battle through five levels, descending deeper beneath the surface while facing hostile aliens and deadly obstacles. All the while, you must monitor your H2, PU, and O2 levels, drained by the hostile atmosphere but replenished by scattered bottles. Jetpack power and a temperature gauge also demand attention, since if any of them drop to zero, it's game over.