It seems weird seeing these drawings at first; but then you realise just how much detail of a video game world can be recalled soully from your memory. This is what Mapstalgia has chosen to celebrate.
I will always remember in shockingly good detail: the Pavlov map from the original Call of Duty (from taking drawings into school to plan attacks for the next LAN game night), full schematics + guard routes for Strut E on the Big Shell in MGS2, and the street layout of Vice City. So far, the blog has been a cavalcade of doodles of differing quality from a vague recollection of Training Ground from Timesplitters 2, to an almost scarily well detailed sketch of Melee Island from The Secret of Monkey Island.
The only way we can explain the feeling you gather from looking through these images is that of pure nostalgia and clarity, as you realise just how much you train/trained yourself to map out your virtual surroundings as you play. It's fascinating.