BattleBlock Theater

In this game, each chapter is divided into five areas: three areas that must be cleared in order to unlock the fourth, which is the Finale. The fifth area contains the Encores but does not factor in here. For this achievement, one must complete the Finale, which is divided into two sections, and acquire a letter grade. Simple, yes? With this, all you need to worry about to get a letter grade are the gems scattered throughout the level. Sure you want to get to the exit ASAP but one should take some time to get some of the gems.

Think of it as you would any other level, in which you want to get all seven gems. Once you complete the eighth and final Finale, a cut-scene will occur and the achievement will pop. Does not matter what letter grade it is. All that matters is actually getting a letter. You can tell if you got one by passing by the Finale dorr and seeing if there are two letters at the bottom. I am not sure if only having one letter will help as I had double letters for each Finale, but you are welcome to try it out.

(If you acquired letter grades throughout the story, then you should also get one of the four achievements relating to getting letter grades.)

As far as I can tell, getting a letter grade simply requires that you finish the level. I've completed levels with one gem (via warp) and still got a C.