Really good game. Could use some more fine tuning though on controls and all. I, like others here, am a little perturbed about the lack of a pause menu (it's obviously needed /: ). Also, as for hard mode, it was too easy surprisingly. Maybe you can add in more types of zombies with stronger hit points - I don't know though up to you. And lastly, I must say I love the katana use in this game. It's bloody beautiful, literally! But I think there should be one more weapon in the game. Maybe a Chain-sword? ;P I mean come on, a cross with a chainsaw and a sword - the ultimate hack and rip weapon in the game. Maybe it can be unlocked in Hard mode, or if you have an "Insane Mode"
All in all, I will say this is a really good game, despite the flaws mentioned above. I hope you take in consideration, a few ideas for the future. Chainsaw Slasher has huge potential.
Cheers, Nayata!
- Eternal