×Entrance:
If you added one more layer of gel, the killing of it would go much faster. I think that doing so would be a good idea.

1W:
A long room, but it required lots of thinking. Good work!

Secrets:

×
The Entrance: As I said, I thought this was a very good room. Cleaning the gel at the end was tedious and unnecessary. Perhaps placing the gel mother closer to the doorway would help.
Also, I'm not sure whether the fuse and bomb contraption really added anything to the room. It is an interesting mechanism, but functionally could be replaced with a closed door that the bomb opens. I'm also not sure it belongs in this room. This one is entirely up to you, however, as I certainly don't feel that it detracted from the quality.

Once West: This was one of the weaker rooms in the hold. A hack 'n' slash room is perhaps fitting, given the "theme" of the hold, but this room was boring. Also, I have not tested it, but I believe that one of the clone potions is unnecessary.

Once North, Twice West: I liked this room. It was long, but interesting. It was a neat execution of a cool concept.

Twice North, Once West: I enjoyed this room, but I'm not sure I found the intended solution. I sliced up the bottom half of the mud and then released the guards so that I could sprint upwards and make it to the islands in front of the slayer. Once I was there I dispatched the guards and then, with a little slayer manipulation, completed the room. Is this intended? The interesting part of the room, in my opinion, was the slayer manipulation. In my solution the guards seem almost superfluous.

Twice North: The first time I played this room I must have found the trick without realizing it. Now I can't seem to re-defeat the goblins. I liked this room, considering the theme of the hold.

×
Holds:
Nanfro Budkin's First Dungeon,
The Puzzle Catacombs
Graphical Mods:
Power Station (AE)

×Entrance: Neat theme, though the endgame is a little tedious. (Perhaps a gel-to-mud token at (30,27)?)

1W: Not hard, but more than a little time-consuming, I felt.

1N2W: very clever!

2N1W: still pondering this one. (Slayer manipulation is not my forte.)

×Entrance - The beginning of this room is an interesting study of brained vs unbrained movement. As others have said, getting rid of the gel mother at the end is a drag. It would be nice to just blow her up after opening all the doors.

1W - A lot of hacking and slashing here. Not as interesting as your other rooms. A player can use a clone to skip past the room. In this case, it's fine, but need to watch out, because sometimes the ability to skip rooms with clones is a backtracking problem.

1N2W - I really like this room. There sure are a lot of golems here, though. It looks like you've provided enough to build a "golem-channel" down the middle of the room, and then some, which is not strictly necessary.

2N1W - As Ravon said, this room has some unintended solutions. I removed the mud before anything, had the slayer open the door to the guards, which I killed right away, and I never lit the fuse. Demo attached.

2N - A fine room, though I've seen this trick many times before.

2N3W - This looks like a very interesting complicated room, and I haven't quite worked out what all the pieces are supposed to do. I was writing about how it was impossible, but then I finally solved it. I'm pretty sure I didn't do what I was supposed to do. My solution mainly involved freeing a mimic. Demo attached (included in file with other demo).

3N2W - If the player goes to this room, they are stuck (when they get back to 2N3W). You'll need to provide a return path.

1S - This is a nice idea, but I haven't been able to solve it. I spent an hour or so convincing myself that this room is impossible, by trying everything I could do with each of the 10 possible starting turns. Which one did I miss?

1N1W - This room looks long... maybe some other day.