I really enjoyed playing this game! I like the simple but effective approach you took. That said, I did notice a couple of issues

It can be a little difficult to know where each box is supposed to go
The first box to come out of the conveyor is not always box 1 - not sure if this is intentional or not
You can also equip multiple boxes at once by loading one, equipping a different one, and then loading that one on the same one as the other one

Overall, I really enjoyed playing this game! I love the colorful city, I myself used a similar style in my game. I also like the pure simplicity of it! Overall, great game, good job on your submission!

I like the delivery driver and the truck, and the driving around is nice. The building don't really look like buildings. Maybe less packages, and to a more specific location instead and not just a number. Otherwise not that much to do.
Also, it's almost impossible to get back on the road when you fall of.. Talking for a friend that could not drive, of course...

I liked the part of game involving filling up the truck and unloading it at the destination, but i think i'd enjoy the overall game more if there was more challenge/spontaneity/pressure to get to the destination. Right now i just iterate through the doors until i deliver everything. I'm essentially playing the game on autopilot

That being said though, this is not a bad game at all, definitely for a first game jam. Good luck in the future!