nice concept, also looks good :) My improvement tips:
- the player doesn’t have enough choice I think. If drones lie around, repair them. If you have spare currency, get drones. Maybe attack some slimes in the mean time. You could add repair costs, bringing a choice between cheap but tedious to get drones (repair) and expensive but easy to get drones (buy). Or add something else you can buy.
- things get hidden behind the farm crops. You could try making the crops semi-transparent.