I finally beat Ultimate Mode! YAYA!! I'd say it's a very fitting challenge for the last stage, although I'm not sure if Ultimate Backrooms is possible to clear in one attempt. Either way most of my feedback about the other gamemodes applies here, with the biggest exception being about Ultimate Bunker; hunting down the keys with three Boofies patrolling the area without having to bring them back was great and fair fun, especially since audio attenuation was changed.
And one more thing. You can softlock yourself in the Ultimate Mode hub by crouching in the corner near Tips'n'Tricks Totem.
Now for my reviews on all the Elaine's Memoir modes since I was also able to beat all of them on Extreme.
The first trial is just alright. Once you get into a rhythm with the demon it all comes down to patience as getting the keys becomes RNG as they start floating around. Wish more was done with the Red Light/Green Light mechanic and the map.
The second trial has a steep learning curve, but becomes enjoyable once you start memorizing the maps. I used to hate it, and maybe Normal Mode should only have the obvious differences, but now I think the mode is a pretty tense challenge that has a lot of "Oh lord did I screw up?" moments. Nothing quite captures the feeling of hearing static, checking all three monitors and not registering a single anomaly. Then you hear static again and well, you get the point.
The third trial was my least favorite. There just isn't much to it in my eyes. You just pick a different spot and then doomscroll until the game gives you back control, then pray you're able to find the demon(s) in time. Then you do it again. Extreme mode had my hopes up that you'd have to find Lonky Lanky and hide at the same time, which would've been an interesting mechanic, but the 1v2 gimmick we see instead just doesn't really add much in my opinion.
The fourth trial is the best of them all imo. The atmosphere is great and the design of the demon works perfectly with it. The mode sort of works like Bunker, with you having to bring items back to the beginning in a set order, except their starting positions are the same every time and can't be changed. Maybe a tiny bit of randomness could've been warranted for the harder difficulties, but since the order is random every time and learning the map is already a challenge in itself I think it's fine. I say this though because I don't really notice many differences in the various difficulties. I was expecting Extreme to make me find every book in the Library with a super strict demon that would kill me any time I flashed the camera at nothing, but it honestly felt no different from Hard. I also don't understand why there seems to be a time limit in the library, and wish that it was communicated better to the player. But other than that, this trial was a very solid experience.
With all that being said, I'm very excited for the future of the Boofie's Bunker series. I'd say there aren't many loose ends besides the ending of Ultimate Mode, so whether our journey takes us back to the Chaos Realm or the Waking Realm, I look forward to seeing the story's conclusion. Best of luck to you with development!