I personally like the palette on the mecha koopa stuff(tm). Being more vibrant than the foreground kinda draws the player's attention to it, which might help make sprites hidden in there more noticeable.
Either way, nice work with the aesthetics so far! The gimmick has a fair bit of potential as well, it could make for some really cool puzzles (which fits with the ghost house atmosphere, I guess).
Siding with Aeon here, I like the palettes. The colors on the curtain go well together. Really digging the slight hint of purple in the ground too.
As for the gimmick, I've seen it many times and I never really liked it because it doesn't actually affect the gameplay. You're just playing a level with two interconnected rooms. I like the little touches with the upside down sprites though!
Instead of judging in my thread, I figured I'd bring my new comments to you in this thread to give it some life. It's already much better. There is a couple problems and comments I have on it, though:
-I now finally realize how you were supposed to get the previous Secret Exit in the first place: You had to feed the Blue Yoshi a powerup to make it come to life, then have him grab the key and insert it into the keyhole. Now you just need him for a Yoshi Jump to get a Coin. Nice.
-I'm not fond of how you handled one of the Yoshi Coins: You have to Item Babysit a P-Switch from the end of the room and back. I don't recommend this. You might want to rethink that coin, or it could seriously affect your score.
-Once again, you forgot to remove another test door. If I were you, I'd put in just one test door at the beginning for testing, then delete it when you're done testing, or just do away with it and just test some areas without the door.
-Thanks for taking my suggestion on making that horror route the secret goal. It's already much better and makes more sense.
-I feel like the midway point comes in too early in the level. Are you able to move it elsewhere?
Level's showing some good improvements. Keep it up.
R.I.P. eXcavator... You will always have a place in our hearts...