Am I doing something wrong? I like the idea and it's actually a very solid base-concept for a TD-game. However, the start seems way, way to slow, starting with 100$ affords me: one blue tower... That has super slow projectiles and a useless range, so one side of the planet will get hit (or even the same side, the tower aims directly at its target, making 80% of the hits miss if its not right next to it or if the meteor is directly above it), I did not even have another 100 after the third wave, and then I always die, as it is. the game is unplayable.
This would not be a issue if you stared with more cash, so I'm guessing the low starting value is just a bug/mistake?
Other then that (even if it is a rather big issue), it has potential. The placement of the towers is very satisfying, and as mentioned from this base you can add so much content. Would have loved to have some more sound effects however, and some smaller details (like the heart icon on the planet pulsating or similar, a moving background etc.) would have been great to make the game feel a bit more alive.
A good entry!