Difficulty Quest

[Pro Killer 171]

does difficulty affect achievements?
:Bounce:

[exodusmonkey]

you can do it all on easy if you really want

[Starstrukk X360A]

The only achievements in which difficulty is an issue are the ones that actually mention a difficulty. If it doesn't, you're good to go (:

[Jappe x360a]

To clarify a little more, there are 5 achievements that require you playing on hard or expert: Mythical Millionaire (1 million points in a song), Hand Mutilator (Beat BWoLP on expert guitar, no powers), Chosen One (Beat FoTS on hard/expert drums), Giant Slayer (Beat HW...TPD on hard/expert bass) and Ultimate Answerer (all stars from one song).

Also the 133,337 point achievement requires you to play on expert, but it is easy as a pie if you use the custom song.

I believe the rest of the achievement are obtainable on medium.
NOTE: Not all are achievable on easy; some band achievements require atleast medium difficulty.