You've essentially made a Crimsonland clone, flash version. Well done!!!
You don't really deserve that 3.5 stars, to be honest. Crimsonland's enemy movement was much more smooth, the bonuses came more often and stayed on the floor for a longer time and level up perks were helpful (Which you've stole so blatantly and making your game that bad compared to Crimsonland) and their survival mode had more of a challenge.
Crimsonland's gameplay wasn't the best. But you just made a pretty fail clone.