This is a very interesting, short hold - I thoroughly enjoyed it. It's a bit like an 'alternate universe' version of some of the official hold rooms. You'll see the famous tar rooms from KDD redone in gel, as well as some clever variations on rooms from JtRH, TCB, GatEB, and one from Suit Pursuit (though admittedly I haven't played SP, so probably ought not to comment on how clever it is in comparison).
My favourite rooms include
1E (although I don't even remember the original from GatEB),
2E (a nice challenging variation) and
4N1W (not too tricky, but fun).
Naturally all of these variations are more difficult than the originals, but I found it quite accessible, so put the difficulty at 6 brains.
A couple of negatives I would mention - firstly, some room entrances unnecessarily don't match up with the neighbouring room - specifically, 1N and 1N1E, and 5N and 5N1W. This seemed like a bit of an oversight, but barely detracted my enjoyment of the hold.
Secondly, I kind of wish it was longer. Perhaps it would have been better if whole levels were re-done, or just more rooms were included - I don't know, but I couldn't help but feel like it was a little incomplete.
Overall, though, don't let those last two points put you off, this is a really cool idea and turned out to be a lot of fun. I'm sure you won't regret playing it; I certainly didn't.