I've join their CBT lately and found out that it is the stand alone successor of Squad/Squadron Tower Defense, a SC2 mod which was heavily based on the original Legion TD mod on WC3. Tyler Johnson, the original creator of the said SC2 mod, has been also hired by the Space Rhino Games (the developer of Breach TD), just like how Icefrog had been hired by Valve to join the Dota 2 development team. The game shares several features with LTD, but with a more competitive twist. P.S. English is not my first language, so please excuse any grammatical errors. P.P.S. Moderators, please just delete this if it's not legal.