Psychonauts (2005). Had this little gem of a game recommended to me by some guys on the GOG forums where it has a cult following. It's essentially a 3D platformer but is completely original in it's story and execution - highlights included setting fire to squirrels and trying to rescue the kids from the camps brains that had been extracted by a psychotic dentist! Designed by Tim Schafer (of Grim Fandango, Day of The Tenticle, Monkey Island) the obscure cartoon style of the graphics mean that it doesn't really look that dated - so much so that for the apparent sequel planned for release next year, I don't think they will be able to make the game look that different without changing the soul of the game - unless of course they do something drastic like what Beyond Good and Evil 2 looks like it's shaping up to be but personally I'll be a bit disappointed if they go down a similar road. Anyway - this game was so refreshing to play, there just aren't many games made like this anymore - 8/10. And by the way - it's going for 90% off at 69p at the minute on the Humble Store!!
https://www.humblebundle.com/store/psychonauts?hmb_source=search_bar
Oh and this is another old game that supports 3440x1440 resolution natively...