Great retro game!
This is a fun game with a retro look that reminds me a lot of Mazes of Tron (the old Intellivision game) except that you can move bits of the "city" around...
Tilt controls work great, gameplay is streightforward and smooth. Being able to start the game at faster speeds is great, and there is lots of replay value due to the randomness of the game layout.
I'd give the game 5 stars except for the following:
1) It's a bit overpriced at $4. I see some comments about $1.99, which I would have immediately went for if I had played the demo first (bought it instead of getting the trial version by mistake, luckily it was a happy mistake!)
2) The game really should have some sort of music, especially at this price. Some light techno or trance would do the trick.
3) The "ball" (players ship?) sticks out like a sore thumb against the beautiful Neon themed walls, 8-bit themed enemies, and piece translation effects. I'd love to see it appear as a neon yellow circle, maybe even leaving a bit of a trail. Or maybe even yellow/green like the circle in the game's icon. Or the blue translucent marble from Marble Madness...
Side note: I also think it would be fun if the arrows (perhaps a double-arrow ">>") would cause the game to scroll sideways for a while, perhaps at a slower speed, and/or up/down arrows to reverse/change the speed to mix things up a bit.