Hey! Thanks for sharing your game :)
The idea is cool, the art is cool, and you did a very nice job on the UI and on the code. Only one bug spotted: I managed to have two items overlap on the balance, but no big deal. It looks very polished.
On the gameplay side, I think the concept is a little weak at the moment.
For a good arcade game, you need the difficulty to ramp up. If the difficulty doesn't change, either the game is too hard and the player is frustrated from the beginning, or the game is too easy and it gets boring. I was in a second case. I managed to hit the green zone 20 times in a row on my first try and gave up.
You must increase the difficulty and challenge the player like: "How far can you go? How long can you survive?". Think Tetris or Missile Command.
You had many ways to do so: Reduce the time, increase the conveyor speed, reduce the number of items, remove a space from the balance, add constraints on the items you can put... You could even combine those constraints randomly to create variety in the gameplay, like you're playing and suddenly, BOOM, you have half the time and you can only use 2 items.
Anyway, good job for creating this in 96 hours :)