The game is played from an effective bird's-eye-view perspective, which allows you to scroll to see the entire level of the reactor. For each level, you must reach a target score by using the droids to perform various functions, such as activate a Geiger scanner, absorb radioactivity, or detonate explosives. There are 6 droids in the game, only 2 of which can be used on any level. The fun and challenge, therefore, is to figure out which droid to use where, since each droid has a different characteristics that make them ideal for a specific environment. The reactor can be shut down only when the core temperature is raised to an appropriate level, and this is accomplished by sending water barrels down chutes or reducing the Entropy level. This means that you must carefully maneuver the droids to move those barrels, while avoiding dangerous objects such as an earthing box which can drain all your droid's power.
If it weren't for extremely difficult last levels that are impossible except for those with perfect hand-eye-brain coordination, Quadralien's unique mix of action, logic, and puzzle elements would have earned a Top Dog status. As it stands, though, it's still an immensely enjoyable, addictive action/puzzle mix that is definitely worth a try. Puzzle experts in particular will likely find the game a good challenge. Thumbs up!