Worms is a turn based artillery game that costs $4.99 and also includes in app purchases.
Pro Same great Worms gameplay but with more strategic elements
At it's core, worms 3 is still the same fun gameplay found in all the previous incarnations of the Worms franchise. However, worms 3 has added two new gameplay elements that increase the amount of strategy in the game, squads and cards. Squads gives individual worms different advantages/disadvantages such as speed or increased damage and you can choose from the various worms to form your team. Cards give you boosts that you can play during your turn such as extra health or weapons.
The upgrades are also not tied to in-app-purchases. You cannot buy yourself the best upgrades and thus the game does not punish you for not buying upgrades.