@Kurz i suggest you http://codecanyon.net/ people are selling their html 5 games specially made with construct 2. instead of selling once for 500$ u can sell it parmanent for 10$ more earnings for long term. i dunno how much percent that codecanyon taking.
its just a suggestion. i personally bhought 3 games from there for our project already. i might buy yours too but not for 500$
and also for 500$, im here have to agree with @grandbrinus your game is well made but its not original and worth 500$ according to the other games you can find from web. im not telling this to you to humiliate your work. however thats the current market