We heard it was coming, showed you guys an early hands-on (video) and now TapSplosion available. Fetching for $1.29 / £0.99 with a free trial, you can grab it here in the Marketplace:

TapSplosion is an accelerometer based action game, you tilt your phone to control the player and tap the screen to place explosions in that position. You have to battle an oncoming enemy hoard which is constantly increasing in size and complexity and always tracking your every move. If one of these enemies touches you, you will explode and it’s game over for you! You get points based on combo kills, time alive and number of enemies on the screen and you can submit your score to global leaderboards and compete with other players from around the world!

The game is a quick time-killer and is certainly challenging enough. Give the developer some feedback on his blog and give the app a shot if you have the time.