The premise for City Jump is simple: You are a superhero who runs up the sides of two parallel buildings, dodging and destroying the obstacles and bad guys you encounter on the way up. You leap from one building to the other by tapping the screen, taking out baddies by jumping on them. The higher up the buildings you go, the more points you score. For every three of the same enemies you defeat, you get a temporary power-up and boost of speed that make you invincible. Mastering when to jump and when not to jump is the difference between a high score and one that you wouldn't dream of bragging about to anyone. If you get a score that you're particularly proud of, you can submit it to the online leaderboards.
The game was a bit jerky on my HTC Droid Incredible at first, but a recent update to the app has alleviated most of the frame-rate problems I was having when I started this review. Although the music and sounds are bearable, you have the option to turn them off should they start to get on your nerves. Something strange I noticed was that the pause menu was just a picture of a TV with a "play" icon on the screen--unusual, but it doesn't detract from the overall experience. The in-game ads don't appear during normal gameplay, seeming to come up only on the menu screen; that's definitely a plus, since they don't interfere with your jumping exploits.
If you're sick of Angry Birds and you need something simple, mindless, and fun, be sure to try out City Jump for some instant gratification.