I have to say, after using SteamOS Windows on a handheld is a non-starter. Linux just performs so much better for gaming on the go.

This is going to be a weird one considering the graphics, but hear me out, the original Deus Ex. Something about the game just feels so well put together that the graphics take a back seat to the gameplay. There is a reason the community around the game has fought so hard to keep it running on modern hardware.