Full disclosure: I also have an entry in the game jam.
Interesting game. Some really great looking maps (I will definitely be hunting down those tilesets). I liked all the flavor text that rewarded the player for exploring (At least on the early maps. Later maps were not as 'flavorful'.)
I didn't see anything in the rules about making changes to a submitted game before the deadline. Hopefully, you will find the following observations useful and can use them to improve the game before the deadline.
With any luck, your game will attract non-RPGM devs on Itch.io. To shorten their learning curve, consider a brief tutorial on the controls at the start. Include that the books are save points. Alternatively, you could turn AutoSave on (System1 tab) so that the game autosaves every map change.
I'm still trying to master parallax lighting myself so know it's not the easiest to implement. However, the lit areas are too circular and don't account for things like walls that would occlude the light.
The two sets of stairs leading to the landing with the first mob appears to have a passability issue. Only the side with the blue stripe is passable.
It was not obvious where all the doors were since they were obscured by the walls and banisters. Perhaps place the events below the player and set them to player touch instead of action button. That way the text window automatically pops up when they approach a door. Also include the name of the map or room the door goes to in the text window (e.g., "The [room name] door is locked. I'll need to find a key."
Consider using the TinyGetInfoWndMZ.js plugin that comes with MZ to popup a window whenever the player gains a key. After the 3rd key, I had to keep opening the Items menu to see which key I had found so I knew where to go.
Oftentimes, I didn't know where to go to find the door a newly found key went to. Perhaps give Reid an inner monologue to help guide the player along. "Hmm, a [room name] key. I recall seeing that door near the [landmark/point of interest]. " Reid also witnesses some unusual things that would surely give him something to think about.
Slow the speed for the credits scrolling text. I'm a fast reader but I had to reload my last save to catch everything.
Good luck!
Neuralsplyce