Simple yet very fun concept. The collision works really well when the ant colony is medium sized, you need to make sure that tunnels are wide enough to fit the swarm of ants going back and forth. Once I got to more than 100 ants, many ants would cluster into balls even though the tunnels were large enough and some of them would stay idle. Nevertheless, I enjoyed it a lot, its very satisfying to watch your army of ants dig a network of tunnels.