If your game is crashing on startup, it might be due to a recent change on the Steam Beta Branch.

You can try switching off of the Steam Beta Branch (located in Steam > Settings > Interface) and see if this fixes your game. This isn't guaranteed to fix, but we've seen it work in a few cases. We'll be further looking in to why this is the case.

(To clarify, this is the Beta Branch for Steam itself, and not specific for BAPBAP)