I was just looking into this the other day. Nice to see someone do it. I wonder if making it more hackable by replacing the electronic guts with something like a ESP8266 would be worthwhile. I'd much rather be able to have a simple little server on this device that I can talk to over the network rather than having to go through some random company's servers. I imagine connecting it to the motor that turns the feeding mechanism wouldn't be too hard and the screen and buttons could simply be removed to prevent any, ahem, manual tampering. Adding some way to lock the food bin would also help with impulse control for those who need it.

Another upgrade would be to randomly reward the desired behavior instead of always rewarding it. This helps to both prevent gaming the system as well as keeping those dopamine spikes high when you unexpectedly get some candy. Using chocolate as a reward is perfect since it provides tryamine to help replenish your dopamine levels.