Fun game with a lot of polish :) Looks really good!
For me on Safari does not w work well, very laggy and no cursor is visible. On Firefox still laggy but cursor is at least there
In the beginning I did not get that I can attack with the cursor. And no idea what hammer does on towers :D
In the beginning, I felt the progress was too slow, like I was just dying super fast (perhaps because I did not use cursor). But later it changed and after each level I felt that upgrades are too cheap, I could buy too many each time so I did not have to bother choosing _too much_
Good luck with the development :)