Space Invaders Infinity Gene has a great concept - take the original arcade game, and then evolve it level by level, making almost a history of shoot 'em ups along the way.
The first thing to say about Space Invaders Infinity Gene is that the controls are great - you move the space ship with your finger, but it's relative movement, so you can play with your finger beneath the ship, keeping the action easy to see. Firing is automatic, although you can toggle it on and off with a three-finger tap.
Starting exactly like the original, with only horizontal movement, Space Invaders Infinity Gene soon frees your movement, and brings in lots and lots of new enemies and power-ups. The levels in the main game offer a great deal of variety and, thanks to their minimalist graphics, always look great. There's also a music mode, which generates levels for any song on your iPhone. This means the number of levels to play is only limited by your music collection!
Any shoot 'em up fan will love Space Invaders Infinity Gene, and it may well be my favorite game on the iPhone. The presentation is perfect, it's accessible yet challenging, and offers tons of unlock-able content. Version 3.0 adds horizontal scrolling.
With cool retro vector graphics, excellent sound, fantastic controls and great gameplay, Space Invaders Infinity Gene is one of the best hand-held games available today.