Really fun game, achievements were a good twist. Not much to say other than what's already been said - seeing how much money you get after each level would be really helpful. Would be cool to have some sort of challenge mode, like fight the lvl 32 boss with no upgrades, or something similar. ^_^
In terms of artwork - it is great. It might even appeal to the female audience there is on Kongregate.
Though the concept in itself isn't at all new and I feel that there isn't really any indication on rewards (say at the night club, people just appear). Not to mention, but this is as a gamer - I kind of feel that its promoting the website a bit too much.
The music, though it seemed a good choice in the beginning - quickly becomes irritating, and seems to loop over and over.
Based on artwork alone and how long that might have taken you - i'd rate overall 2/5. Though I do believe there could be major changes that would be beneficial to the game.