Thank you for the feedback! Most people leave nice little notes which I appreciate, but a long critique is worth much more.
I agree, the art is something I need to do sooner. I do it last-minute and I'm not an artist so this is what we get :)
I wanted to add more levels that are tactical (as opposed to fast-paced like the survival level), but ran out of time to add much beyond tutorial levels. Of course, the survival level seems to be everyone's favorite, so maybe I should have focused on that!
(As for HTML version, I will try to do that next time, but I've had weird performance issues in the past. I do want more players though so debugging that is probably worth it)