I don't think gamepasses are allowed, so this won't have any gamepasses or event items involved in this.
The easiest way to practice is the skip loading trick. It does not remove the loading screen, BUT you can move while it's still loading. Just memorize each path that you have to go down with the skip to get further ahead!
The second way is to try and memorize each level and path. This is heavily required with this run, as things get randomized. I suggest studying a map from the wiki to help!
The third way is to practice doing each boss as fast as possible! There is a trick to this, pull out the sword and spam click while moving your camera slightly. This will do some extra damage to the boss.
Good luck!
Boss Tower and Retro Resort have both been added as miscellaneous categories to the full game section. I do understand that Retro Resort is behind a pay wall (unless you have already completed it) which is why it and Boss Tower are in the miscellaneous category. Feel free to voice your opinion in th