Sega Master System / Mark III / Game Gear
Cast in the role of a time soldier (surprise, surprise) the player - or players, for there is a simultaneous two player option - has to breach the barriers of time itself in order to rescue five troopers who are lost across the aeons, and ultimately defeat the evil being, Gylend, who sent them there in the first place.
Basically, the soldiers have to negotiate a series of vertically and horizontally-scrolling landscapes representing the different time zones, and battle any indigenous hostiles that appear.
On destroying specific enemies, additional weaponry becomes available and is simply picked up to add temporary impetus to the assault. No surprises at the end of the level either: a guardian being manifests itself according to the period, and must be wasted before attempting the next era.
The SNK coin-op wasn't brilliant and, unsurprisingly, this version doesn't improve upon the matter. The visuals are sparse, the action is a little slow, and unfortunately after a few goes it all becomes a bit ho-hum.