The bomb can be passed hand by hand or at distance by throwing it.
I used trigger zones for that. It has a timer on it and I check each
frame if the timer is under 0

The first step is to cross projectiles and avoid them.
So I used C# coroutine to spawn projectiles with a random amount of time
I used Trigger to teleport the touched player to the position of an empty
object placed at the beginning

The second step is to cross a labyrinth but we can go
through the big doors only if we have the bomb in hands
So the player will have to throw the bomb over walls.

The final step is simple, you have to walk on the slab of your colour while having the bomb
in your hands to desactivate the slab and permit your friend to walk on it.
If you walk on it without the bomb in hands or if you walk on the wrong color, you are dead.