I could be wrong, but I don't think you're going to have success with anything but the most basic games for a dog. If there isn't something about the game that the dog immediately finds fun, it's probably not going to be interested in it. A video game is not like one of those toys you can hide treats in, where it'll be obvious to the dog there's a reward to be had. Dogs have to be trained in types of play that don't come naturally to them and the reward isn't immediately obvious, like they have to be trained to use an automatic ball thrower.
When young children play video games, they'll often become obsessed with some silly small aspect, like trying on different hats, and ignore the entire rest of the game, because the trying on hats part is fun for them, and they don't really care about other potential fun they could be having. I imagine a dog would behave similarly. I think it'd be very hard to design a game for a dog that has some obvious thing that will immediately attract its attention, and not have the dog end up obsessed with that part, ignoring the whole other part that's there to make the game more challenging.
If the goal is to keep the dog exercised and entertained, you've already achieved that. Animals like repetitive games. It's less likely they'll get bored of it like an adult human would.