I will update the game, my plan is to have more levels that get larger and larger, until you finally reach the speed of sound (it is actually the hardcoded max speed of the game and it was achieved by one of my playtesters with a glitch !)
And i'm not very happy with the current shop, what I might end up doing is that in the levels you can find the upgrades wich will go into your shop so that you can buy them. And I might also let you switch through bought upgrades while running to let people make combos with them.