Galaga Legions offers an addicting style of play as well as provides a substantial challenge for any high score junkie. The lack of game modes (only two!?) and any semblance of multiplayer is a big strike against fully making this a "must purchase." Especially since games like Geometry Wars 2 and Ikagrua offer a very similar gaming experience.
The superb visuals and thorough sounds don't disappoint when compared to some of the best games Xbox Live Arcade has to offer. Although 800 Microsoft points seems a bit high priced, Galaga Legions is a solid addition to any games library.