The game isn't terrible, but there are some obvious design flaws.
1) Grinding - level 3 gets you more money than level 4 and is very easy. This could easily be fixed by making the boss there either a one-time event or just a lot less rewarding after the first time you kill it.
2) Variable damage - this has to go! Since I was mostly a knife fighter (yay, infinite ammo!), I found it very frustrating when a guy that usually takes 3 hits to kill would take 4. This would throw off my timing and let other enemies get within striking distance, especially once they started coming in freaking swarms.
3) Targeting - once again, as a knife fighter, this killed me many times. A guy would be hitting me, and the knife would attack a guy behind him without hitting him. Other times the knife would hit three guys, but sometimes it would just hit one, and three out of four times it would be the wrong guy.
Finally, the opening cutscene just froze at one point. I clicked "skip" and that worked, but I felt like it was supposed to end without me clicking on anything.
Good game in general, you just need to fix some issues.