Source: Aliens (1986) Movie
This is actually a combination of 2 parts of the movie. The portable motion tracker, which shows the distance/angle to sources of movement, and the auto-sentry display (but that one was only in the Director's cut, not the theatrical release)
Objective:
Kill all the xenomorphs.
How to play:
You have to aim the turrets yourself by dragging your finger along the motion tracker, then click either of the sentry displays to fire.
If you keep firing a turret too long, it'll overheat. And you can't fire it again till it cools down.
You have a limited amount of ammo per level (500 rounds per turret), and 4 turrets total.
If a xenomorph makes it all the way to 0 meters, you lose a turret. If you lose all 4, it's game over.
The bottom part of the motion tracker has some helpful info:
F.E.M.S. [Xenomorph detected].[Bullets detected].[What angle you're pointed at] ( [distance to closest xenomorph] .00 m) CX. [Left-most Xenomorph]/[Right-most Xenomorph].[Current Level]
The higher the level, the wider the range of angles the xenomorphs will attack you from, and the faster they'll run at you.