In any game you make there are going to be certain concessions that you can make to accessibility, and ones that you can't. On paper, it's not "worth" spending a lot of effort in order to reach a small number of people. But in a bigger sense, we're all human and nobody wants to leave anyone behind. Because we want everyone to be able to play together, (and because we're human) we tried to make Rock Band as accessible as possible. Sometimes we succeeded, sometimes we didn't.

Leftys: We've always tried to help the 8% of the population who is left-handed. For Rock Band, we wanted to make it even easier to flip your instrumentation left to right. One little detail you may notice about the Stratocaster is that the strap peg flips from the top to the bottom of the guitar, so that the guitar will hang well for lefties. Similarly, we moved the high frets down from the base of the neck slightly, to better match the left hand divot in the guitar body. We also put the whammy bar in a more central location to better adjust to left-handed positioning.

Small or limited mobility hands: Lots of people have small hands. Some of these people are young. Some have hand injuries that prevent them from spreading their fingers. Some people are just petite. For these people, we kept the high frets accessible during regular gameplay. If the regular fret spacing is giving you problems, try the high frets.

Short / Tall people: After making some adjustments to the leg lengths, we tested our drums with a range of people from 7' to 4' tall. They play well for everyone within that range, and we're pretty sure they would play well with people even shorter or taller.

Color blindness: About 1% of the population is color-blind. We've actually done color studies of our user interface to make sure that, if not ideal, it wouldn't completely be unusable by color blind people. The contrasts had to be high enough for differentiation by people with various types of colorblindness. Thankfully, Photoshop filters exist to make the detection process much simpler, but once we did find issues we had to go through a time-consuming process of re-balancing our colors.

Tone deaf people: Not really a disease, but we did keep easy-level singing generous enough that anyone, no matter how tone-deaf, should be able to play by eye.

Unfortunately, there are always some people you can't reach, and Rock Band is no exception.

Photosensitive Epilepsy: Sadly, we ran out of time to do anything for the .01% of the population with Photosensitive Epilepsy. When we looked into it, our systems were just too entangled and hard-coded to change in such a fashion without slipping our release date. Hopefully we can do something on our next project.

Blind: We've kicked around the idea of having menu options narrated for blind players, but getting it done right would be a huge amount of effort. Plus, except for singing the actual gameplay would still be inaccessible. We did try to make everything as visible as possible to help people with bad vision, but that helps everyone else too.

Similarly, we've thought about how to make music games for the deaf, but this was not destined to be that project.

Really, we'd like to reach everyone out there, but in some cases it just isn't possible, and in others it isn't feasible without shipping much later. Hopefully we've struck the right balance of helping in as many people as possible, and still getting onto shelves. Two weeks, people! Just two weeks!