All right. Here are the results of my first playtesting session. I'm omitting what's already been said.
- Hitting Tab in the first room of the first stage transports you to the clockwork stage.
- Trevor still vibrates against walls.
- Trevor can't throw his axe while crouching.
- Trevor can fall off of the stage select platform. Freeze.
- Dying at the same time the boss dies still glitches the game (Trevor revives, stands, and can't be controlled. Freeze.)
- You can hit monsters through a platform while you jump. (happened at the beginning of 2nd clockwork area)
- The stopwatch clock animation hides certain blocks. I'd suggest putting it in the background.
- Gear jumping is too uneven. I've died too many times because of Trevor's choppy movements or the jump button's failing to work in certain places.
- Allow post-game over respawns at the beginning of the stage, not at the beginning of the game. Make passwords actually work (or am I not understanding something)?
- You can fall off the invisible outer edges of the screen. Not recommendable.
The more trivial ones:
- Hitting the bone tower in the first stage with the very tip of your whip doesn't seem to do any damage.
- Jumping straight up while keeping the jump button pressed displays a split-second "standing" frame at the very top of the jump.
- Hitting a different directional button while whipping changes the whipping direction mid-animation.
- You can hit the skeleton's death animation, and it can damage you (although it doesn't seem to in the clockwork stage?)
- The pendulum jumps are great, but you're 'redirected' too abruptly to the center of the pendulum. Make it feel more like the moving platform the original had.
- Candle-dropped items never disappear.
The aesthetic comments:
- Music much improved. You should release a soundtrack.

For the title screen, though, I preferred the guitar version. You can hear the MIDI-ness of the current string version, and it's a bit underwhelming.
- Great opening, good music. But why MoF Trevor? Doesn't fit with the game. It may just be me, but I'd suggest original DC Trevor or at least CoD's Kojima Trevor...
- The second stages might need some extra ornamentation, especially the woods stage. It's slightly bland as it is. You might also try to reproduce the background effect the original had. Great owl mechanic, by the way.
I might update this once I'll have stopped losing all of my lives in the gear jumping sections. Try to get them more polished.