I looked at your project and it is very nice. i can tell you put a lot of work into it and a lot of programming. as far as 2d tower defence goes this is one of the best i have seen. keep up the good work and finish the project.

my only concern is that the regular person would not appriciate the game. every one is too spoiled with 3d content and would pass by this game at first glance. i do not think it would be hard for you to make the transition to 3d it seems that you have a great outline for the tower defence game. if i were you i would look into makeing it 3d to appeal to a wider audience. the best tower defence game i have ever played is tower madness for the iphone.

anyways i do think you should finish it. althoe it looks about done now really for the most part. good luck and have fun