Yes this is worth the caps lock!
Not only was the memory trail for the final food pellet, the brown one, there is an entirely new mode of play and exploration!

Upon loading into the cage, wait a few seconds, then look to the right next to the mousewheel.

You'll notice that, if you already completed the final food pellet, a peculiar circle will appear. Run up to it!
Explore every nook and cranny of where you into!
More to explore coming eventually!
You might be able to tell that the game mechanics are starting to branch out into potentially... crafting...
(Or at least getting materials and 'spending' them)