nice effort , if you plan to work again on it , you should consider adding a music and sounds effects (a lot of musician can offer you a sound track for free, if you put them in the credit (including me, pm if you want), a restart button is also crucial , a few monsters and upgrades/bonus and you'll have a nice game. Hope you will continue your work :)
Thanks to Zillix the developper : ! A really great gameplay, something very ingenious about it
and we should considerate the great music too , so + if you also want to says " good job " to Jim Peterman . ;)
Ah?