You could try Medi Evil for the PS 1. Originally, it was set in the 800s (according to the official website), though it was retconned by the sequel to instead take place in 1386 (so that MediEvil II would be set exactly 500 years later, and possibly to make it less anachronistic). If memory serves, the PSP remake, MediEvil Resurrection, uses the newer year.
I AM NOT A TREE
Dude, I fucking loved that game.
NO TREE FOR ME (ALSO LOVES HER BOYFRIEND)
I was all ready to say that the thread starter answered their own question. The age is Dark because we know so little about it. It's low on those vivid little details of everyday life that are so important in world-building, historical events or places to recreate, and plot hooks with some depth. From a pop culture perspective the Early Medieval is basically an inferior version of the Late Medieval, because knights, plate mail and most of the other interesting things haven't happened yet. You may as well compensate by adding pixies and dragons. Copper or tin for Widdershins.
Then someone brought up vikings. Go look for vikings.
Because after the fall of the Western Roman empire, Europe had little to no access to the graphics technology that would allow them to make said games; even the Arab world mostly imported its processors from China.
Oh, wait, it meant set in the Dark Ages.