Fight a bunch of fast zombie-like creatures of varying toughness, and the military out to stop said zombies.
There are checkpoints aplenty, so dying is an easy step back. Nothing seems excessively tough, but it's not a cake-walk either. Perfect balance between hard and easy. The story leaves you a bit vague on purpose, but is interesting enough. It seems short, but anything longer would seem too stretched. One BIG boss is incredibly tough, and constantly throws so much at you, you think you'll never beat it, but you'll manage... after dying multiple times. The last boss seems anti-climactic after the earlier HUGE boss, but when you realize you can't seem to damage him... it gets some perspective. A little ingenuity will win out in the end. After the boss is dead, you're dropped back in, to clean up any left-over mini-games you want to complete, or just keep destroying everything in sight.
Fun, good graphics, feel Super throughout. Story might be a bit short, but there's plenty to keep you occupied if you do everything. Only one negative; after the story is over, cleaning up the rest seems fun, but once you realize it's never-ending, you'll lose interest.
All-in-all, well worth the time playing.