Dude the VFX are awesome no doubt. Loved the enemy death FX, loved the bloom on the blades. I think this is the the only game that I've played so far that has such carefully crafted VFX.
I think the single biggest thing you should do for your next project is add SFX. I know this isn't any concrete gameplay advice, but from an overall perspective, I think you should start to focus on SFX too. It's such a core part of the overall experience.
As for the gameplay, I personally didn't get very far so I can't comment much. I'm not a great gamer, so I got stuck very early on. I realised that I needed to wall jump up a tunnel, and I literally physically could not execute the moves required. I don't think it was hard (the other commenter clearly made it through) but its more of a skill issue. I tend to have a lot of trouble performing mechanical skills in games. So I ended my run there - sorry!