Pretty good conceptually as a first game jam submission and ambitious as well. I like how everything's presented and the story present within it too, plus all of the interactables as well, but I do believe that you already know some of the points that fall flat and I hope my own feedback won't be repetitive with what others have already said but my main point is that some of these puzzles do appear to be difficult for some people to get a grasp at for one reason or another.
For example, the first puzzle the interpretations of it are a bit too many, such as my own: My first was interpreting it as the numbers on the portrait beside the door as a reference and then the green numbers on it being an 8 since I figured I'd try something that was more blunt at first. The problem for me came with the X Green where I figured it meant to multiply the prior number by whatever Green was. With my interpretation coming out wrong I turned instead to consider alternatives such as Green meaning the Yellow and Blue numbers added together since they mix to green or maybe it was all in reference to the coloring of all the objects in the area/across all three rooms since those colors were present between the three rooms/the last room. I was stuck on that part till I checked these comments to figure out what the X Green ultimately meant, but that's part of the challenge whenever it comes to balancing out puzzles.
This part may have been my own overthinking of the situation, but these things can be very tricky to get right depending on the person, because if the balance is off and the puzzle is the blockade, then that may just be the end of the game for a player eventually. That all said, I'm not going to fault you for that, it is a tricky thing to get right and as we had mentioned before in my own post you responded to, this is part of the experience to come with this kind of thing that you can better implement later. Plus it's better for this experience to come up in a Game Jam rather than a published game where that can seriously hamper your own reviews of it. I think it's best to try to view the puzzles from different people's perspectives to see what conclusions they make come to upon looking at it or maybe to account for where those interpretations can go awry because of one scenario or another. But conceptually the ideas present are very solid and I think the depth to the puzzles and the interpreations of them just need better balancing out between the two in order to make something wonderful for all.
I tend to go into detail like this for things that I get a bit passionate about in the hopes that it can possibly help, but of course that is my own... terribly complex perspective/feedback on it. I very much like the ideas present here and the game as a whole but I figured perhaps it'd be helpful to give this feedback to try to help the craft of it all coming together maybe better if you do find it to be helpful, otherwise oops I did a ramble. Regardless, it's a good game very much so for a first time jam game. I hope you can keep up the good work.
Viewing post in After the End jam comments
Yeah, a lot of people had some trouble with the safe puzzle, but after seeing the collective feedback from everyone I already have a list of changes that would make the game better!
I hope when the full version does get out (maybe like August) you and the others get to play it, thank you so much for playing and giving feedback on this one :D