Possessed MATTAN, I found a few bugs in your submission.
1: Look here. I can walk through the walls!
Walk any further and you die.
2: What the hell? Is Mario on crack?
Here's a better view.
You can get here by going left from where you fall into the Masks' trap after waking up in your bed.
3: I have the key! Let's go down the pipe!
Wee!
D: Someone took my key!
Oh yeah, you can get stuck next to the door that gets you into the bloody part where the hands are. You'll be stuck in between two pillars waiting for a mask to get you so you can die.
EDIT: It seems I've found a secret exit of my own. Did you plan to have this in, MATTAN? Anyway, in the end where the goal post is, be sure you HAVE YOSHI. After, get the secret 1-up. Now, this is where it gets tricky. Position yourself at the EDGE of the block. Make it look like you're kind of floating. Now, Run to the wall but don't run INTO it. When you're close, jump, then dismount Yoshi. You should be on top of the edge. Now, fall to the side, and you should be out of the level.
Oh, also, why'd you have a shortcut to get past the Time Machine, MATTAN? Was it for testing purposes? I'm talking about the pipe that replaced the 1-up's location in your first version.