In a surprising approval by Microsoft, TapSplosion 2.0 just became available in the Marketplace. Why surprising? The developer wanted to add a bunch of Achievements to the game but was worried Microsoft may consider that term 'exclusive' for Xbox Live titles--which is not too far fetched--and deny approval.
Luckily, it made it through and is available in the paid version of the app (he may add it to the free version eventually, but the dev believes such things should be reserved for full editions of the game). Sure, none of the achievements count towards your Xbox Gamerscore, but it still adds a nice extra bonus to the mix for 3rd party games and something else to strive for.
You can grab TapSplosion 2.0 in the Marketplace here. There's a free trial and it goes for $1.29 full.