That’s a good idea to have two separate but related gameplay on the same screen! Solid gameplay. I don’t like the fact items are disappearing from the ground if you don’t collect them fast enough, because you also need to stay on a different place to get upgrades.
One small addition that could be interesting would be to force the right-side gameplay to be more rewarding if you engage with it. For instance, special bonuses or obstacles. It’s entirely possible to play the game without interacting with it at all, which is too bad because it’s a really cool part!
Well done :D