Trial #1: The beginning.
The solution is really simple, you've to beat the parkour without falling into the lava.
Trial #2: Blind Maze.
Follow the green path, from the start to the button.
When pressing the button, you have 30 seconds to reach to the end. Follow the blue path while running.
You can follow the red path from the start if you want to read the hidden sign that means there's a button.
Trial #3: Spider Path.
Green points at the photo below are safe points. Just jump over glasses avoiding webs.
Trial #4: Fall or forget.
The solution is really simple, just keep crouching (LSHIFT, B or CROUCH button) at the edge or the soul sand block, and then, jump.
Trial #5: Save your breath.
Swim through this path to get to the end:
Trial #6: Choose or lose.
1st door: choose the left door. The right door will take all players back to Trial #5 (with checkpoint included).
2nd door: choose the right door to the Trial #7.
Trial #7: Spiny Path.
Wait until you've got all hearts, and just jump over the cactuses to the end. You can keep crouching at the edge of the cactus to avoid taking damage.
(Some blocks at the limits have been removed for avoiding collisions with the player)
Trial #8: So close yet, so far away...
Follow this path while crouching (LSHIFT, B or CROUCH button) to get to the end:
Trial #9: Accurate shot.
Just shoot to the three objective blocks. When you get 3 out of 3, a wall will break to your left.