Congrats for your game ! :)
Stacking things feels good, and not having a lose condition was a good call I think
In the current state of the game, there's no incentive to use every object, and you can just discard what you don't like and use the cars and big boxes that are easy to stack. Some ideas on how you could improve that :
- having wind that shakes your structure, to encourage you to build wider
- having some sort of penalty for every item that falls from the platform ? (but that goes a bit against the idea of a chill game)
Food for thought !