CastleMine
CastleMine from Mugshot Games combines tower defense with a little bit of old fashioned digging. Instead of mapping out mazes for creeps to crawl through or building balloon things on green green grass, you get to dig underground one block at a time. Uncover extra gold deposits, additional resources, or even nests of enemies as you attempt to defend your castle from the threat from below.
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Hey, Castle Mine is available for Windows Phone too.
Oh, there is a free (with advertisement) version on WP too!
No Android, nor a full version on the PC? Ah well, I must pass.
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