As in the original Steambirds for iPad, Steambirds Survival HD puts you in command of a small squad of cartoonish fighter planes – but instead of active movements and firepower, you'll simply draw their paths, equip them with power-ups, and hope like heck they survive to see another turn.

It's a design recently cribbed by Crimson: Steam Pirates with aquatic success, but the original aerial approach holds up very well in this sequel, which swaps out individual campaign stages for battles against increasingly tough waves of enemies. Along the way, you'll earn coins for downing enemies and completing objectives, which let you recruit controllable allies and unlock later stages.

More than 60 missions spread across eight cities are included in this initial release, with seven more cities coming via updates. And it's even slicker than the original, thanks to help from Halfbrick, the maker of Fruit Ninja and Jetpack Joyride. A separate iPhone version is also available, which delivers a comparable experience; and though they're both free, I wish it had been one universal release, so users could share the unlocked content and progress between devices.

The bottom line. The strategic turn-based method delivers hours of cerebral entertainment, but unlike many free-to-play releases, you don't have to pay a cent to enjoy everything Steambirds Survival HD has to offer – though a $2.99 in-app purchase unlocks all stages from the start. Either way, it's well worth the download.