On slide 2 you can do the ice + slide + 10 box to get the bottle. Inside there's a new mechanic that I don't find a good place for her
I haven't managed to get the slide 2 bottle with less than 11 boxes. I retried. If you have a less than 10 box solution, I am curious!
I can get to slide 1's secret with 12 boxes and no other secrets known...
this is the best I can do on the secrets
