itch.io

I got it by accident, I don't remember exactly what I did but notably I factored 147 with 6 cards in hand to keep the 49, then used it to clear all freeze.

I couldn't figure it out either, and after reading other posts I saw something I missed - to try to give a better hint without spoiling it:
Read the note in the 2nd box in the 3rd room. What stone is it referring to?

If that's not enough, I'll put the solution at a separate link (idk how to make spoiler text): https://pastebin.com/q9kcg3Sv (but I recommend trying it for yourself)

Cool game, but why does Papu try to get potions when at full health rather than saving them?

The game crashes (Browser version) at the start of the second level, but I'm glad to see another second-person shooter (yes, I've seen one before).

However, you might want to add some text in the description explaining what it is for people new to the concept.

Got all the coins.

The game went a bit slow at the start but picked up nicely at the end.

However, I'm unsure if it's an endless runner if there is an end that isn't your failure to keep moving the trolleys away. (I wouldn't know what happens if you hit a trolley, I didn't hit any).