So as Kanomus has pointed out, there are some obvious connections between this series and your other games. Is this project a part of the BTNverse (perhaps a culmination of sorts) or are the references simply Easter eggs? I would normally assume it is part of that collection of games, but there is a noticeable lack of the signature [BTNverse] stamp as a precursor in the title, making me a little wary to making assumptions. It would be very helpful to piecing together the lore and it would let me know if I need to play through the BTNverse series if you wouldn't mind giving the community this particular sliver of information. As exciting your games are, The Sky is Lava in particular is not a task that I'm prepared to partake in unless I'm certain there's a correlation (that game simply is a nightmare to play- I've made it to the point where EEv is separated from Adma in the autoscroller but lost my progress after getting stuck there). Thank you for your time, still waiting most anticipatedly for Jan 18!
Most of this checks out with what I found, although the monsters appearing in part 3 are separate from the rainbow ghost entities who can be found appearing for a short time in the trees so you may want to change that theory. Also I do believe that time travel refers to the player restarting.
This is definitely the hardest installment so far. It's taken me this long to get just endings 1 and 4. Even so it's definitely the one I've enjoyed the most, probably because of the lore implications and the satisfaction of doing anything at all competently in the disorienting landscape.
I certainly think you could, but changing the mouse hitbox like you did really got me to the difficulty level I wanted it to be at and the levels themselves were really enjoyable. I'm just worried that certain players requiring what effectively is advertised as a baby mode to complete the game might not have the effect you are looking for. If you changed the mindset and instead changed the reduced hitbox to the default mouse hitbox and used the current default difficulty as an extra challenge mode with maybe a different ending it would improve the overall experience. Obviously do whatever you want its your game these are just some thoughts from a player.
I think that this game was really well done, although I will agree with the general consensus that the mouse maze section was just a little too difficult. I was able to complete it with the easy mode but it left me unsatisfied as a player about the accomplishment. Is it possible to change that to the default and have a toggle-able "extra challenge" in the settings. It might have the effect you are looking for in the balance. Otherwise it genuinely impressed me. You took what other indie horror games on the platform are doing and took them to the next level in a way that doesn't feel stressed or forced. Keep doing what you're doing!
That last level was brutal.