Excellent update to the classic with gorgeous understated space visual, tasty sound effects, and that classic swirling-alien-ship gameplay, now with many additions including obstacles (asteroids), warp boosters, boss battles, branching paths, ships that merge in to bigger ships, ships that split in to smaller ships, ships that split in to smaller ships and later merge up again, ships that grow when shot, and the option to start with two ships side-by-side, as if one had already been captured and rescued.
Really there's nothing not to like here if you like non-manic vertical shooters at all. And to come back to those sound effects--they're really some of the nicest sounds you'll hear in any game, ever. Even the happy little ditty accompanied by skipping alien ships on the high score screen is stunningly pleasing. Lovely.
The stage 2 background is a little rough on the eyes, and your ship's shooting sound can get old. : P Also, the scrolling action parts in stage 2 are not that fun, with the difficult-to-destroy things in 'em, but at least they're short.