Please forgive my extremely long review of this game, I've played through it a few times and have a lot of thoughts.
Considering you're 14, and the fact that this is a jam game, there's a lot to like here. I enjoyed the music and sounds quite a bit, and I think the world you've come up with has potential. I think the storytelling is a little too on the nose sometimes, I feel like you could imply a lot of what's going on rather than having characters spell it out (for example, have Coward try to justify his actions and show his pride in ways other than flat out saying his pride consumes him.) The text could also use a bit of proofreading, as there are some inconsistencies (Coward being referred to as "Coward Cow" in some places, inconsistency on whether he is a millionaire or billionaire, etc.) In a game that focuses on storytelling and worldbuilding, getting details like this consistent is pretty important.
The mechanic of investigating and looking around different objects, while rudimentary, also has a lot of potential for environmental storytelling. I won't be too critical on this point because I understand with it being a jam game and only having 3 days, fleshing out the mechanics would have taken more time. That being said, if you continue to develop this style of game, I think it would be good to think of more ways you can incorporate information than just what's on the surface level, like having your character's comments on the things they see indicate their opinions on the things they're observing, or writing on top of a newspaper showing the perspective of another character on the events of the news.
In a similar boat of not being too critical due to the time constraints, I feel like some of the puzzle design could use some work. I thought the piano puzzle was a cool idea, but the capitalization of "PIANO" and "FACE" made the solution somewhat obvious. I'm not 100% sure how I would improve it, though. (Maybe something like a crumple in the note that in some way highlights the word "face" or some sort of repetition of the word in multiple notes around the room could work?) On a sort of different note, the final puzzle with the lights, while I think the one with the most potential, struggles due to there being no indication what the first color in the sequence is. A little indicator light for the first color in the sequence on the corner of the box would make the puzzle less frustrating once you've discovered the solution. I would also suggest the sheet that explains the corresponding colors be made to be something that would exist within the world, like maybe one of those chemical information sheets? Puzzle design is definitely a very hard thing to get down, so I think trying your hand at more puzzles and having someone playtest the puzzles might be helpful in the future.
I feel like a weakness the artstyle faces is pixel inconsistency- I'm not sure what your art software is, but if you want to keep with a pixel art style, I recommend trying out Piskel as a free option, or Aseprite if you can afford it in the future. Pixel consistency can be a hard thing to manage starting out, so I'd suggest looking into guides on how to make consistent pixel art, but it makes a world of difference in a game's art so it's something I'd recommend focusing on sooner rather than later. Considering the game was made in 3 days, I think the art is pretty solid, though.
Overall, though the game has shortcomings, I had a good time with 90 Seconds and hope you keep making games! My review may be critical in areas, but I hope it comes across that I more than anything hope you can improve in the future and make really cool stuff. I think you have a lot of potential if you continue to work on worldbuilding, and I appreciate how you've managed to tell a whole, complete story in a game made in 3 days! (Heck, my game barely has an ending because I made it in the last 2 hours, so I definitely understand the effect time constraints can have on storytelling.) I'd recommend maybe trying to make some more small games like this outside of a jam setting to work on building worlds while having the time to polish your projects. Good luck with your future games!
(Also, like Cryob said, I'd suggest a web build in the future, it does help with ratings quite a bit.)
