Just testing if this feels good. a,d,< arrow,> arrow, move you left and right. j and up arrow make you jump. I will not update this anymore because I can't add items and have them be stable.
The bug {Corner clipping} is basically the wall jump from the first Mario Bros game, if you landed on the perfect pixel and did a frame perfect input, you would get a second "wall" jump. Corner clipping works like a more forgiving version of the wall jump, if you get within 20 pixels of a corner and are holding the jump button and moving in the direction of the corner, you will get a second jump. This is because of the way the jumping works in the engine, you can only jump if the level isn't touching the hitbox, so when you touch the corner it thinks it's a ceiling until you move out of the way and it will make you jump again.