How hard is it to dev?

[alexybubble]

I've always somewhat wanted to work on an emulator before, but I've always been so completely intimidated by the prospect that I've never attempted to act on the urge. However, as time goes on, I continuously get more and more annoyed at the same 3 or so games staying as the only games that don't boot on the emulator for multiple years at this point, and it makes me really want to personally take a look at them to see if its possible to fix them. As someone with relatively little experience in this area, is this something that could reasonably be done?