The graphics look good. The puzzle idea is interesting but with just one level there's not much to say. I pressed 1 and 2 and tried 3 then back to 1 - turned out it was the correct combination. For a starter level that's good difficulty. But it also made me realise that I didn't learn anything - how the logic works.
It's nice that there are descriptions next to the towers but maybe there should be some overview of the types of towers at the start of the puzzle which don't involve moving the camera around.