Alien 3 (Megadrive)
The player's task in game is to rescue hostages and defeat aliens which have taken over human colonies. There is a set amount of time to complete this task in each level. Failing to rescue all hostages results in instant death, as well as not reaching the exit before time runs out. Some hostages are extraordinarily well hidden, e.g. in chambers behind fully solid walls. Only stage 2-2 requires the player to not rescue hostages and run straight for the exit. Stages 3-2 and 5-1 are basically just rescuing hostages with no enemies to fight (5-1 has one Alien just before the last Elevator)
The player carries all 4 available weapons by default with a limited supply of ammunition: Machine gun, flamethrower, rockers and grenades, all of these are shot with aiming with the D-pad and holding down for rapidfire. It is possible to also pick up limited supplies of other ammunition throughout the levels, cycling between each weapon (and the standard gun) with and using them with . jumps. To rescue a hostage or pick up an item, simply touch it.
There are 5 worlds with 4 stages each. A boss type Alien waits in the 4th stage of each world, although the same boss is recycled for all encounters. The game has no continues and no password system and must thus be cleared in one sitting, which can take ~1 hour when familiar with the stages.
The difficulty level affects the amount of ammunition and time granted to clear a stage.