There are some video game levels that will haunt you forever. The Water Temple from The Legend Of Zelda: Ocarina Of Time, stage 6-2 from Ninja Gaiden, and pretty much all of Cuphead each inspire enough frustration to ensure you won’t forget them anytime soon. But for a certain subset of obsessive gamers, there is one level that has caused more trauma and broken controllers than any other: 4-2 from Super Mario Bros. This is surprising considering, if done correctly, the level should only take about twenty five seconds.

Recently, YouTube user Summoning Salt took a break from making insanely detailed videos about speed running to get even more granular about why this level is such a pain. On its face, 4-2 seems pretty simple. You make a few jumps, hit a secret block, and climb up to the warp zone area that gets you to world 8. But if your aim is to finish this level as fast as possible, these jumps have to be incredibly precise. One minor flub and you could lose a precious second of game time.

Things only get more complicated when you start incorporating glitches. It turns out, there are two secret exits in 4-2. There’s the vine you climb to the warp zone and a pipe you can take down to a room of coins. Speed runners realized that, if you could force Mario’s sprite a little bit forward on the screen, it was possible to trick the game into thinking the warp zone exit was still active even though you were going down the much faster pipe. Numerous versions of this “bump technique” used to push Mario forward a few pixels were developed over the years, some easier than others.

As recently as last year, a new, even faster tactic for completing 4-2 was developed that involved clipping through a brick wall. And—if you’re worried this discussion about video games was getting to dry and academic—you’ll be happy to know the technique was developed by a player named xx_420_blazit_xx. Though this method currently reigns supreme, speed running fanatics will undoubtedly continue to toil away at 4-2 for years to come.