It's easy to like Astro Tripper, the latest frenetic shoot-'em-up from the makers of Live Arcade's Mutant Storm series. It's just difficult to get too excited about it. It's a solid and enjoyable PSN arcade experience but it never quite finds the hook, or achieves the sublime crescendo, that defines the best of its genre.
For reasons left wonderfully unexplained, your lone spaceship must zip to and fro across fourteen horizontally-scrolling stages. The goal is simple: clear out all the enemies and you move to the next level. The circle button flips your craft over so you can fly swiftly in the other direction, or you can fly backwards if you want to fend off encroaching aliens as you retreat. On the harder difficulty levels, you can even fall over the side of the level, putting even more pressure on your nimble navigation skills.
You have two attack options, swapped with the square button. The blue laser attack offers focused power directly in front of you, while the red sweeping attack will hit broad swathes of enemies above and below your position, but does less damage. Periodically, power-ups appear and boost the size, strength and range of whichever weapon is selected. Scoring, meanwhile, uses a simple cumulative multiplier that ranks up and offers bonus points for consistent destruction, but starts to decrease should you allow your onslaught to slow down. There's a time limit for each stage as well, just to keep you moving.