An explanation on how I decided on the games lists (I'll update the OP).
Quite simply, I went through the list of exclusives for each popular platform (obviously) and selected the most highly rated games of 2013 based on Metacritic results.
The top 30 games of the year choices are based on this, and include top platform exclusives, sprinkled with some of the big name titles that didn't actually make it up the Metacritic rankings but still deserve a mention because of their impact (CoD: Ghosts and Dead Space 3 for example).
I'm hoping this method caters to a broad audience.
Dividing it further into categories becomes a hell of a lot of work, and makes the survey daunting and less approachable. If you want maximum results for these things, you make them as simple as possible.
In some cases, PC for example, there are obviously way more games than I can possibly list, but getting past 20 titles had us into the realm of unknown and poorly rated games. I excluded expansion packs as that introduces complications and bumps off standalone games that might otherwise get recognised.
The Xbox 360 situation is obviously a bit of a joke, but I included it to make the point.
For PS3, I excluded anything that is also on PS Vita, so we had true PS3 platform exclusives, and then the Vita category can have its chance to shine.
Wii U and 3DS obviously enjoyed loads of Nintendo exclusives.