Rohrleitung Gate is a puzzle-oriented ROM hack of Super Mario Bros. that was inspired by the time travel anime Steins;Gate. It was developed by the same person that created Celeste Mario's Zap & Dash! and features a great level of technical prowess. A number of features were added that weren't in the original Super Mario Bros. such as two-way screen scrolling, the ability for Koopa shells to break bricks, and background parallax scrolling. It also has a number of bugfixes applied to the original engine to prevent cheating, making it incredibly difficult, if not impossible, to execute wall jumps and wall clips.
chatterbox nonetheless isn't deterred and sneaks in a few wall jumps to beat the game and get the normal ending as fast as possible. There is a "best ending", but it cannot be achieved without editing the game or using Game Genie cheat codes. For more information on this and the details of the run, you can read the author's notes.