An idea for an ending I had would have objects at each shop after looping where you can store lives, after you die it would take you to a final boss stage where you would regain all the lives you stored and depending on how many lives you have after you defeat the boss it would reincarnate your spirit as different creatures. It would have been really weird and taken months to make so I decided to just release the game instead.
And in the first shop all the items linger for a second after you take one, jumping out the side of the bubble and using your momentum to gain enough speed you can get a second item before they vanish.