I'm not able to recreate the collision issue you mentioned, there is one known bug if you hit a 90 degree corner just right you can clip through.
As far as the movement, it isn't delta-time compensated, so if your not able to run at a consistent 60fps your movement could feel weird, it's tight for me, but there is a low pass filter on the camera that could make it appear delayed.
For my playing experience, it can be challenging but it is far from impossible. It's only two short levels so it needs to be "nintendo hard".