A typical assault mission will take you anywhere from 30 to 45 minutes to complete, with the later missions taking even longer. If you quit, your progress will be saved so you can pick it up later, but Sentinel 2 doesn't offer a save system in game. The ability to pick up where you left off is key to this game, because most players will only have time for shorter play sessions. Sitting through an entire assault mission in one go-round can get tedious, and so speeding up the game's pace (via a fast-forward button) is essential to not only fight off the alien hordes, but boredom.

Sentinel 2 offers a lot of firepower to deal with its thin selection of alien forces. Some of the game's best moments are when your defenses are being overwhelmed, the aliens are knocking down your barriers, and you're forced to call in a missile strike to wipe out the map. The weapons and the aliens aren't particularly original, and neither are the powers, but combined the elements create an enjoyable, if at times tedious strategy experience.

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