Lenke responds:

-- when monsters where frozen in frond of my tower, the tower still takes damage.
A)is not a bug, in frozen can't move, but can atack xD!

- after lv 11 I couldn't use one of the missiles (fully upgraded)
A)mmm... "add capacity" is (x2). if the 2 not appear, could be a bug.....

- after lv 12 the missiles disappeared when they were shot
A)the last creature(blue) shoot balls who random's disable your missiles :)!

those following below aren't real bugs, just some improvements:
- more lv's//no add more because no have save data, and i don't wanna boring you :)
- more upgrades// i think in more upgrades but....:p
- better graphics (would be nice)// could it be, but my graphics are not the best xD!
- monster description, and maybe a monster guide, to see which monsters are weak against the elements.//propably i added this and a discard button....

that's all :D