Played through the game and this is what I think:
For the most part of the beginning, it's really the same thing with some added polish. One thing I noticed is that the screen boundary teleport in the grassy area [forgot what it was called] still activates at the 4:3 boundaries instead of the 16:9 boundaries. Either this is a mistake or it's for speedrun purposes, I don't know. It just looks hella weird. Finding the Shotgun threw me for a loop as I was not expecting it at all. Another good thing is that the Fireball Boss Skip still works so I was able to get through the first boss quickly. I didn't expect the floor to drop though.
I like the shotgun jump mechanic. It took me a while to figure out but I put two and two together and figured it out. The last thing I did before writing this section was get the Spur. Holy oh my god yes, the fucking Spur. Thank the heavens. It was a little hard getting it, but a tip for others also having trouble: What I did was stand in front of the statue, jump, immediately start aiming down, and as I went up I spammed the everloving shit out of the Shotgun. It should give you just enough height to land on the ledge with the Spur chest.
Now from this point on, I'm writing this live as I play.
An ominous door. Let's see where this leads, shall we?
Oh. It leads to a room with those white annoying dipshits. Great.
Nevermind, they're easy to take down with the Spur.
Chest? Chest. Let's Shotgun jump up there and-
OH MY GOD YES.
(And it's the 2.0. DOUBLE OH MY GOD YES.)
Oh hey, a normal day in the United Kingdom. (Because wind. Ha, funny joke. Cough.)
I like how you can see the previous areas in the background. Nice touch.
AND UP WE GOOOOO.
Oooh it's ominous. It's ominous in here.
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
OH MY GOD I BEAT HIM. I BEAT FUCKIN BALLOS WITH A SPUR AND LIKE 14 HP WHAT THE FUCK AAR
I refuse to jump in that hole. If it's a secret, it's a secret. If it's a pit of doom, I will die. And I refuse to do Ballos again-
Oh it's required. Okay then.
In we go then.
Wait, am I back at the original ending door?
Yup. Beat the main game without a single death. GG Aar. Maybe re. I don't know.