Zen Studios has announced that its tower defense / puzzler CastleStorm is making its way to iOS and Android this Spring as a free-to-play game called CastleStorm: Free to Siege. You may have figured that out on your own considering it has free in the title. If so, congratulations!

This upcoming mobile port will feature 4 playable nations, each including its own campaign that will span some 150 levels. It will also offer spell types that were not available in previous versions of the game, and will include a redesigned control scheme that is suited for the touch screen platform.

Zen Studios is also running a private beta on Android devices, which you can sign up for right here.