This video doesn't cover a few of the puzzles that serve as introduction to the game's mechanics.

At the start of the game, go left, hold E to carry the box over the door opening trigger then continue left to find the yellow key



Start the moving platform and jump under the fourth ceiling lamp to find the red key



Jump up the ladders to find the blue key



Drop down and hold left to find the white key



Don't go in the rocket and jump to the right to find the black key
Jump a few tiles earlier to catch the ladders, but don't worry if you miss it, a checkpoint is near.