From the Super Mario Wiki
Parallel World is Parakeet's first official course in Super Mario Maker, released on November 5, 2015. It is set in the ground theme for its main area and in the underwater theme for its sub area, as well as in the New Super Mario Bros. U game style.
The level begins with several wall jumps, some past some Grinders. Mario must then kick a Koopa Troopa into some Brick Blocks, then press a P Switch and continue past the Brick Blocks to reach a segment with some Colossal Koopa Paratroopas, then enter a Warp Door to get a Super Mushroom from a Hidden Block. Mario must then continue through the next Warp Door and climb a Beanstalk to an area where he must break some Brick Blocks to proceed. Afterwards, Mario must enter another Warp Door, and kick another Koopa Troopa into a ? Block to reveal another P Switch, which he can use to proceed into a warp pipe. Mario will be led to an underwater section where he must swim past some spikes. Afterwards, Mario must continue through two warp pipes, and be led to an area much like the main area, except underwater. A series of P Switches and Brick Blocks follow, and they lead to Bowser and Bowser Jr., which Mario can bypass if he wants to. Mario must then bypass some Thwomps and some Cheep Cheeps before reaching a segment with Burners and sideways trampolines, and then a segment with vertical warp pipes and Fire Piranha Plants. Afterwards, Mario must avoid additional Big Thwomps and enter the only warp pipe not spawning Big Lava Bubbles. Lastly, Mario must hit one last P Switch, and travel across the Brick Blocks to the Goal Pole.