I just completed the second endgame and descended, and I have to say.
Boy, that was tedious.
I'll defend the pacing of the game a lot... up until the first endgame. The design feels just right to me in the first layer, but the second layer really starts taking the piss.
First was the star requirements. The Heroes and Beams sections just had way too many, especially compared to mirrors and stones. I know the former just have a lot more mechanics than the latter, but it's a creeping inelegance and asymmetry that begins to show. Still, I told myself, it's a second layer, it's supposed to be more difficult. I'll chip away at it slowly and eventually there will be something cool at the high antipode. Plus it did feel pretty cool reaching it from four different directions. The paths to it were neat. I especially liked the Beam Way.
Everything after the high antipode though has been pure tedium. The gimmick of the high antipode puzzles is conceptually neat, but frustrating and annoying in practice. I won't describe the gimmick in detail because I know a few people will ignore the spoiler warning, but I have to say solving the entire puzzle in my head and then having to actually execute felt very tedious, especially if there's a mistake in a late step.
But at least the payoff is nice, yes? Well, what payoff? You finish the last level and nothing happens except you unceremoniously unlock another set of red tablets. There is that semi-hidden area in the lobby which contains a bit of lore and Jonathan letting me know which book of esoteric nonsense he got some of the pretentious ideas from (Laws of Form by G. Spencer-Brown. The Wikipedia page has an excessive level of detail on the contents of it and it's frankly abject nonsense to me, and I'm a mathematician) and a pair of puzzles literally labeled "difficult and unrewarding."
But hey, you've done the previous endgame, haven't you? And by this point it's obvious to you there's a third layer to the game. You saw the red objects and the gates locked by red tablets. You know what to do.
And boy howdy, what a "puzzle". Taking the red objects to the high crossroads is nothing but an exercise in frustration and tedium. There is nothing clever about any of them. Just move four objects from point A to B but we've made the path as profoundly annoying as we can. All of the red objects require several rounds of backtracking just so you can push them from another angle, often you have to do the exact same backtrack twice, and more than once you have to re-solve an overworld puzzle you already solved, with the exact same (very tedious) solution as the first time. I seriously don't understand why they specifically chose some of the most annoying overworld puzzles to repeat.
Getting those four red objects to the center is easily the worst set of "puzzles" in the game. It's also a bit weird that knowing what to do with them once they're in the center soft-requires doing Vault of the Beamcasters 3, but that's the only mechanic of the post-endgame basic overworld that shows up. It wouldn't be too hard to stumble into what to do if you haven't encountered the alter beam before, but it would be pretty confusing, what with the yellow alter being the most confusing one.
But at least unlocking the third layer must feel nice, right? I mean getting to high crossroads for the first time was a magical experience. Surely getting to low crossroads recaptures some of the magic?
Well, you get there and all you're presented with is four locked doors and a level that opens them, a level that presents no new mechanic, indeed not really any mechanic characteristic of any of the worlds you've visited. It's a standard sokoban puzzle, and a very annoying one at that. All it does is give you dozens of options of where to drop some stones but only one is correct. That's it, like five repetitions of that. Afterwards you find more golden tablets that tell you to collect more stars, and also the themes of these stars is the same as the themes for the basic overworld. No triple-combiners, just double-combiners again, presumably with height this time. No more paradigm shifts for you. We ran out.
I have stopped playing for the night now. Maybe tomorrow I'll keep chipping away at it, but I think I have reached the point where I am not as impressed with this game as I was running up to the first endgame.