There are no real glitches in the run, just some exploits/ninja solutions. The warps are entirely developer-intended (by selecting an area on the map in the pause menu, you can warp to areas you've unlocked), though I certainly never found out about them till I started learning the optimized speedrun. You warp back to the cave entrance after obtaining the orange, red, and yellow shards in any% (and possibly in 100%, but no one's routed that yet) because you can skip going through a lengthy room that exists only to hear one of the letters from Mom. You warp to the town after obtaining the green shard, thus skipping four puzzle rooms and a lot more walking. (I suspect this was a developer oversight, the possibility of skipping those four rooms)
Twice, both at pretty much the beginning of the run, you also select "Restart Level" in order to warp. First is right after obtaining the light blue shard, this warps you back to Hue's house, saving a little walking time, and the second is just moments later in the cave. When you shift to light blue and make the rocks disappear, it takes the miner quite some time to shuffle off-screen (and it's another few seconds before you regain control of Hue anyway). By selecting "Restart Level" there you can simply shift to light blue again and run past the rocks without waiting for him.
My PB has pretty much all the current tech for the run. I fabulously miss one skip in the university three times (and don't even try a fourth time, instead just doing that room's intended solution), but the attempt is there so you can at least know what I'm referring to.
Actually, there is one bit of tech my PB doesn't have. This video isn't the fully optimized strat (if you shift to orange immediately upon entering this room, no further shifts are needed), but it gives you the idea --
That one is a LOT harder than it looks, you lose buckets of time if you miss it, and it's pretty late-game, so I haven't mustered up the courage to try it in a run yet.
Let me know if there's anything I can make more clear for you. Hope to see you doing runs sometime!