Elevator Action by Taito, original arcade release in 1983.
A popular older game, EA (like those initials?) is fairly fondly remembered by many, and still comes up in conversation to this day. For some reason, though the theme was pretty cool, the game never washed with me.
The game puts you in the shoes of a secret agent. An opening sequence shows you infiltrating enemy-riddled buildings by zipline; once inside, you must plod through and look for red doorways as they contain documents which must be stolen. All the while, the building denizens are out to get you, blasting away.
The key gimmick here, unsurprisingly, is the use of elevators. Enter one and you can, as expected, control your vertical ascent or descent through each building. You must be careful not to get shot (of course), or squished above/below elevators if you happen to be hanging out in the shaft.
EA isn't a bad game, it's fun for a bit and there's a bit of challenge; it just seems a little half-baked, like they were hoping to get something a little more addicting out of all of this. As it stands, worth a look, but I don't think most will hang on this game.