I like to do this with games I have several playthroughs completed in. One of my favorites is Bloodborne, with so many sequence breaks and glitches that can be done as soon as you start the game that you can basically tackle whatever area in whatever order you want.

This is the most recent and consistent setup for the COOKIE skip, which is done in the starting clinic area and gives you immediate access to the Forbidden Woods:

Bloodborne Skip to Forbidden Woods (Current Patch)

Once you get that you have access to a ton of late game resources and weapons, and if you combine it with the Shadow AI freeze glitch (which is incredibly easy to do) you can reach Rom in less than 20 minutes, stock up on supplies and upgrades, and break the game wide open.