Shoot To Kill does like a grenade and fragments into multiple versions
From paid and free to iPhone and iPad
When high score, wave-based shooter Shoot To Kill originally came out, it was free but used an interesting method to make money.
Called Free for Freaks, it was like putting money into an arcade machine so that when you died you'd be able to use a Continue. The deal was 10 Continues for 99c; the point being freakishly great players wouldn't need to pay.
Since then however Shoot To Kill has been released in three more standard versions
Pay for pussies
There's now an HD version for iPad, priced at $1.99, a free HD Lite version featuring six of the 24 levels, plus the 99c iPhone Shoot To Kill: Addictive as Hell release.
The two paid versions tweak the original freemium method offering a full Continue enabled game from the off, plus a multiplayer mode, four Survival games, and for the iPhone version Retina graphics. Achievements are supported with Game Center.
You can see how the game plays in the following video.
