Metal Slug Mobile, Digital Bridges' fairly successful mobile version of the SNK arcade classic, will remind you of how much fun it can be to run in a mostly straight line while pumping a battalion's worth of grunts full of heavy metal. The game might not be as great as its NeoGeo brethren, but it's enjoyable enough to dissipate a day's worth of aggression in about 30 minutes of all-out assault--which is a golden ratio for cell phone games and a bargain on any level.