Here is a 100% pen platformer engine. I never really ended up doing anything with this, so I'm just posting this for you all to make your own games with. Arrow Keys or WASD to move. Falling Below -25 y will kill you no matter what. Press q to enter the editor. Arrow keys to move in the editor, space to place a block, x to scroll through blocks, and c to go to Beginning of block list, which is the delete block. Any other things can be found in code. Feel free to use to make your own games with this on 2 conditions, you give me credit in your game, and you love and like this game.
Everything in this is by me. I just decided to make a nice little parcore map for you.