Ret's Escape Puzzle World is a Super Mario Bros. 1 ROM Hack created by Excel in 2004. The levels were designed to puzzle and frustrate players, sometimes by gruesome level design, and other times, tricky puzzles.
There is also a secret fourth world after you manage to complete the hack, along with a hidden warp pipe in World 4-4 leading to a mysterious level that tests your Big Mario skills.
This TAS created by me solves the levels quickly and beats Chatterbox’s (티어) TAS by 27.45 seconds due to great optimization.
The only downside to that TAS is that it loses 21 frames in World 1-1 due to a slower clip through the wall.