The steps in the guide seem to be incorrect. I followed the instructions, but the puzzle still can't be solved.
Sorry for the delay!
I just tested it, and it does work ^^
Here are the instructions again:
i. Smash the 8th mushroom (blue/dotted).
ii. Smash the 3rd mushroom (blue/dotted).
iii. Smash the 1st mushroom (green/claw).
iv. Smash the 4th mushroom (red/circle).
v. Smash the 5th mushroom (purple/lined).
vi. Smash the 5th mushroom(purple/lined).
vii. Smash the 5th mushroom (purple/lined) again.
viii. Smash the 4th mushroom (purple/lined).
ix. Smash the 6th mushroom (green/claw)
x. Drag the blue/dotted pellet (pellet in the top row) to the first mushroom (green/claw) to turn it cyan/arch.
xi. Drag the red/circle pellet in the bottom row to the fourth mushroom (green/claw) to turn it yellow/z.
xii. The path right will open.
maybe you missed one of the steps? You do have to smash the 5th mushroom 3 times in a row. Keep in mind that breaking a mushroom will change the order of other mushrooms, so make sure to count which mushroom is in the position mentioned by each step of the instructions!