Can imagine this being a very mobile friendly game concept. I can second Sergeant Arcades suggestions. With a mouse cursor it is pretty hard to play, so upgrades in that direction would be great, if you target PC / mouse players. Some more suggestions/ideas: As the upgrades are collapsed, show somewhere in that corner if new upgrades became available (maybe as a number next to the "Upgrade" button, or next to the collected crumbs number. When clicking a cookie, some rewarding particle effects might also help raising the fun.
The twist you found has some good potential, wish you luck with developing it further.