Bit.Trip Runner crashes immediately on boot

There is a very easy way to guarantee you get a perfect score -- simply play on "PERFECT" difficulty. You automatically fail the level if you ever miss something that would contribute to a perfect score. Thus the levels become, simply

! = main level completed perfectly

!! = main level & retro warp level completed perfectly (So PERFECT score!!)

If you don't want to restart your save file and play through every level again, however, here's a general guide:

The trick to getting Perfect scores is simply a matter of getting all the gold, and performing all score increasing actions in a single run. In perhaps 90% of the cases, getting all of the gold will get you the perfect score, and there are only a few outliers where you have to make an effort beyond that of simply collecting the gold.

Here are the actions that score points:

• Kicking through a breakable object (Crystals, Stop signs, Boxes)
• Hitting a Springboard
• Bouncing off a Spring enemy.
• Reflecting a Bullet
• Picking up Gold
• Picking up a "+" object.

When given a diverging path with a choice (i.e., either hit a springboard or pick up a gold piece) always follow the gold and the "+" multiplyer, as these two objects are the biggest score boosts by an extremely wide margin.

When given a choice to either hit a points item or survive, chose the latter. Some points objects merely exist to present false choices - going after any item that will result in your immediate subsequent death is not required to score the perfect.

After nearly giving up, I found the answer on Gearbox's forums.

From the post:

• Delete Borderlands 2 in Documents/My Games (not WillowEngine.ini)
• Stop cloud storage in Borderlands 2 Steam properties
• Verify cache in properties
• Activate the nologo option :
• Launch the game and turn off automatic detection in launcher's config (put all options in off or lowest possible)
• If the game start, it will create a new profile.bin... Quit the game and put your saves (not the corrupted profile) in the correct folder. Restart the game.

It does seem that this causes the well known issue that causes badass rank to get reset, however. The Gearbox forum post listed above provides information on how to manipulate it using Cheat Engine, but I'm personally going to wait and hope for them to release a fix that recalculates it automatically.