Having watched all of StoryTeller Gaming's video
https://youtu.be/7WUSWR8mAjU?si=36hBrk_0gdo6fO_K
I spotted several mistakes that needed fixing
Level 01 - The Lost Valley
Removed a floating tree
Fixed a note typo
Added a ramp to certain rocks to avoid the player getting stuck
Level 02 - The Swamplands
Fixed a note typo
Level 03 - The Tunnels
Added collider to cave rocks to avoid player's head looking out of the map
Moved the rock in front of the secret maze to make it a little easier to find
Filled in a hole that enabled players to slip through the map and fall into......infinity!
Filled in a hole behind a waterfall that enabled players to slip through the map and fall into......infinity!
Level 04 - River Canyon
Added collider to cave rocks to avoid player's head looking out of the map
Level 06 - Swamp Canyon
Added a rock to cover a tiny hole in the rock face
Level 07 - Snow Caves
Added an ice ramp in the level to hint at the open cave area on the right
Thank you StoryTeller Gaming. Great video.