Its nice! I feel that the overwork mechanic was not really explained - that bar above the donkeys represented 'hunger'? and when it would fill up they had a chance to escape? I didn't really get it, could use better symbolization that thats what it is, because they still got to that "hunger" state when they ate carrots - which was supposed to be the rest place?
Other then that it was fun! I liked the fact you got a constant supply of donkeys which you just continue to overwork. The upgrades themselves felt meaningful. Great entry, good job!