From the directory listing:
iBomber Defense combines classic tower defense gameplay with the intense action and strategy of the original iBomber games. Keep enemies at bay all over the world using a variety of weapons and tactics, from rattling Machine guns, explosive cannons and awesome anti-aircraft artillery!
Two things that I'm loving about iBomber Defense. Firstly the chance to play as either the Allied or the Axis forces adds a nice twist to the game, but the main tweak is that your tower positions can all take damage. As well as earning money to buy more towers and upgrades, you'll need to balance that against keeping your existing forces in a suitable condition for the fight!
We'll have a more detailed look at iBomber Defense over the festive period, but for now you can grab the trial version for the Nokia Collection from the Windows Store (if you're looking on your phone, try in the Nokia Collection section).