Love the input controls, especially how right out of the gate the menu feels almost didgetic - it's really cool how you just have the menu options floating in space as something you shoot/click.
I had some issues when I stood on the fragged bits of the enemies - if they were spinning they caused me to spin, a little annoying.
From Boat level onwards it gets quite hard! Especially the Matrix (the platforming might be asking a bit much for first person perspective). I liked the difficulty though as someone who's quite versed in FPS it felt difficult despite the AI not being the smartest.
Tip for those on the Clown Car: ignore the back left door. Shoot a few times in the hallway to alert them then pick them off. Clear the room, then back right room, then disarm.