Another cryptic achievement description.
This is a completion percentage based achievement. Whereas 'Livin' on a Prayer' is for unlocking 50% and 'One Hundred Percent' is for unlocking, well, 100%, This achievement is for unlocking 75%.
I played on Easy to make this much more manageable. Completion percentage increases by completing levels (First on Story mode, then on each subsequent mode) as well as getting an 'A' (or gold) rank on each level.