pupil project?? ôo

You should add sound effects and a speed up button.
Instantly better.

Monster system very simple
1

eh Well organized. Needs music. Nothing too new.

After playing this game for a while, I found it enjoyable, but see room for improvement.
This may be a small gripe, but having it highlight green for areas the towers can be placed would just look nicer and make more sense, it's not totally needed but a small improvement that could work.
More tracks: granted this could take a while, but a tower defence game needs more maps, because after a while, playing the same 3 can become quite tedious/boring.
Music: I know it can be hard to make music, but the track I feel just gets boring quickly.
Newground intergrated badges could be a nice addition, considering the game has in game badges, it could work nicely. Granted I don't know how hard this is.

I see room for improvement, as of now it is quite good, just pretty simple.