TFU2 Difficulty Achievement Question

[MajinMikeyX]

OK, so I beat the game on Medium and got the achievement for beating it on Medium and it includes the one for Easy too. When I get around to beating it on Hard and Unleashed, do I have to do what we all did for TFU1, and make a new Save Slot and choose that difficulty and not change it? I noticed that in the Level Select menu that each level shows what difficulty you completed it on, like it says "Completed on Medium", kinda like Halo 3 and Halo Reach if anyone's familiar with how that works.

 

Do you think we can just go into level select and choose Unleashed and re-beat all of the levels until all of them say "Completed on Unleashed" and get the achievement that way? If so, that would be easier since you're halfway through on getting your force powers upgraded and since this games a little more challenging than its predecessor. Plus, I don't want all of my save slots filled up like they were with TFU1 and I'm sure the rest of you wouldn't.