Sequel Gimmick...

I got this game when it was free and, although its an entertaining game, its gonna get deleted once I clear the final (4th) level. The opening story/explanation caught my interest and, as far as Tower Defense games stories go, it worked while remaining believable. Tower selection seemed thorough, yet lacking any real character, and I really like the idea of the "Repair/Harvesting" drones however, a tower with a piercing capability was noticeably missing. Also making the distinction between path and building ground was a little too complicated at times -especially when you like to play the game on full speed, like me. Now, I havent played the newer ones but some of these problems have probably been addressed, so I wont be too critical of this game with my star rating But in summary, the games definitely worth a check while its free (I, personally, wouldnt have even payed a dollar for it), but falls short of other quality titles in the app store of the same genre...

OO7OOO about Sentinel: Mars Defense, v1.8.3