Play the game here : https://store.steampowered.com/app/2948030/Deep_Sea_Sweep/
The levels I use in my game to teach the players about the main mechanics of my game Deep Sea Sweep. The game is a 2D platformer where you must bring a treasure chest to the submarine to clear the level. You can swim in all directions, but once you pick up the chest you are affected by gravity and can jump. You can then drop the chest to be free again. You die in one hit, and the chest can be destroyed by spikes and the void, failing the level.
First small jump, then second max height jump. Using pearls that appear only when you carry the chest to show the path. I force the player to go under dangerous urchins to show the carried chest has not hitbox. Then 2 more jumps with a risk to conclude.
Back and forth that emphasizes the limitations of carrying the chest and introduces turtles as useful platforms.
New enemies, in a level showing the existence of secret ways. These are rarely used for progression but rather for hiding optional star coins. The player can test it right away in the next level. I place coins half in the wall to show something's amiss.
Introducing shooting enemies, and harmful ink breaths. The first enemy slows the new player so that they see the squids shoot their bullets before rushing. The one star coin to get is behind an invisible way, hinted by projectiles going through the wall.
Showing switches that get activated by the chest. It's an incentive for the player to try dropping the chest on the floor if they haven't yet. Then they can figure out how to get past the ink flow.
After having dropped the chest, now forcing the player to drop the chest mid-fall. Then they have to do this during a jump. Then repeat with a slightly tighter jump in which an enemy can attack you.
Showing the player falling chest kills enemies. 4 dropping challenges, #1 and #3 have margin for error with a turtle bringing the chest back up if you drop it too far, #3 has an enemy attacking. #4 needs a drop from apex of a jump.
Dropping challenge but on moving platforms, then also avoiding enemies.