Honestly, it depends on the game and/or genre. Normally, I stick to old school platformers and old build shooters, ya know, the ones that Phil will claim he "grew up playing.", but as I've gotten deeper into my mental illness, I've gotten better with age and skill.
Any old school platformer will STILL kick your ass, unless you've mastered the game and know every jump, every power meter, etc....I grew up playing the HELL out of Castlevaina, Mega Man NES/Mega Man X series and those games STILL kick my ass, but I have fun playing. Am I a pro? FAR FAR FAR from it. There's people out there that are MASTERS of both series I just named and can run circles around me in speed, difficulty, and gameplay. Unlike Phil, I don't consider myself a "pro gamer."
Old build engine titles like Blood, holy FUCK! Blood STILL kicks my ass on anything above normal. Hell, even Blood normal is CBT. Same with classic Doom, which I love and still play to this very day, and "Hurt Me Plenty" on classic Doom is always a good time, however, it's still a TOUGH time. Unless you've mastered circle strafing, time your circle strafing to a SCIENCE, and trust me, it's a science, Hurt Me Plenty is going to HURT you plenty.
Normally, I stick to those two genres of games. Sometimes, I'll dip into others for shits and giggles, but mainly, that's my preferred preference.