Guns'n'Glory WW2 is the latest offering from HandyGames, who also brought us Aporkalypse - Pigs of Doom and Cyberlords - Arcology. This is a very well made tower defense game with several real time strategy elements, and despite being sick of tower defense games in general, I rather enjoyed it.
Where the first Guns'n'Glory was set in the wild west, this one is set in World War II, if the title wasn't obvious enough. I'm very pleased that you can play as both the Allies and the Axis for once. This game changes a lot from the original, and adds several new elements which make it feel like a totally different game.
The thing that immediately sets this game apart from other tower defense games is that your troops are constantly mobile. You can drag units around one by one, or you can simply send them to a specific spot automatically. Rather than have pre-set troops on the map to buy, you have barracks to purchase troops from with the silver you collect. Each level consists of defending your base against the attacking troops. You have three buildings to protect, each one worth a star at the end of a battle. Enemies often come from multiple directions, which is where the mobility of your troops comes into play. It can be a real challenge to keep all of your troops alive and in the right place.
The game has really well done art, and everything feels polished. There is a lot of depth to the game, from the multiple difficulties to the permanent upgrades you can buy for your troops. It's a very different beast from the original game, and while I'm not sure everyone will like the changes that were made, I thought they were excellent. Openfeint achievements are supported as well. To top it all off, the game is completely free, albeit with annoying advertisements. You can buy out of the ads for about a dollar, though. Definitely give this one a look.