Not a bad game, decent music and mostly fun. The scale of earned money is off though- there's no point in buying the smg when you can get the rifle about as quickly. Increasing damage output is entirely irrelevant- a rifle at 60 damage does as much as an energy gun at 36. If you continue a saved game, you start over with the pistol (really?), and the scaled by which the prices increase doesn't match the income you can realistically get.
So all in all, not bad- but there are a few glaring issues that make it stop being fun. :-/