Get a class that can do some consistent damage throughout the game, mainly berserker/frozen fighter/wizard or bloodmage. World selector is a good gamepass to select the best worlds but I personally don’t use it. Learning how to flick your screen can be really good for dealing maximum damage with swords. Swords like piercing blade, katana, cinnamon/candy, and true dragon are really good. Try to stack up on items that can one shot rooms like fast forward, bomb, even spells, and try to gain as much stats as you can. Hope this helps
It really depends on your class. Wizard needs as many worlds with fire and ice weakness to use arcane spell as effectively as possible, so I go embers edge (it has a lot of rooms that are skipped), mount whirl, fungal jungle (cause parasite droids are weak lol), gingerbread (because it has a lot of rooms that are skipped), elemental heights, chill hills, overpower plant (because it doesn't have crystals), midnight casino (it is surprisingly easy), and skytop citadel (because it doesn't have too many different room types, and a lot of them have pyro or cryo droids or are skips, also no acid)
I am in the process of making a speedrunning tutorial if you are interested in hearing more. But this is generally my go-to world choice for speedrunning.
Also, different classes have different world choices. For example, for relic I change gingerbread out for lavender Alps and embers edge for sandy.
For bloodmage, I change out casino for mech and usually also skytop for atomic. Also sometimes embers edge for sandy canyon.
Some world you NEVER want to speedrun include: echo, stone, junkyard, scorpians, dragon (if you are on mobile), and crystilline. They will most likely kill your runs pace
