Obby Creator is a speedrunner's dream sandbox. You get the full building kit, so I can lay a section out exactly how I want it and then grind that route until it's frame-tight. The movement is consistent enough that once you find a line it repeats every single time, which is everything, no random physics stealing a run. The killer feature is that you can build an isolated practice segment, drill one brutal jump fifty times, then splice it back into the full route. Community-made courses are hit or miss, some troll builders bury unskippable RNG or instant-kill sections that nuke any serious attempt, but the well-made ones are perfectly optimizable. For building and routing your own gauntlet, nothing else comes close. PB-grinding heaven, easy favorite.