Lots of the major entries have been said already, so I'm going to go with Mega Man 5. Phil played all the NES Mega Man games in a row one summer back when he was still doing LPs with a camcorder aimed at his TV and they are all awful, but 5 was the worst. He used a walkthrough for the boss order of course, but he also wasted tons of time getting the collectibles in each stage that give you Beat. At one point he was reading out loud from the walkthrough and complaining that the guide is wrong about the location of a hidden collectible (spoiler: the guide was not wrong, Phil is an idiot). Also he frivolously wasted all his energy tanks and died a bunch of times on the final boss, wasting five minutes farming energy between each attempt. It was a disgrace of an LP.
This reminds me of one of these Mega Man X games where he constantly jumped in Sigma's face, unable to dodge his attacks because he forgot he could wall jump. He wasted so much time, it hurt.
Or let me remind you all of his Bayonetta playthrough where he couldn't find the hole in the fence in the very first map and wasted - what - 15 to 20 minutes jumping and shooting around like an idiot (it's a bug dood!) ? Or the time when he wasted another lifetime jumping and shooting around because he forgot he could walk on walls, so basically just again, wall jump?
Or when he wasted
hours failing at the optional special-rule fights, just because he is some kind of worst achievement hunter in the cosmos.
Oh, he also used basically just one weapon the entire time.
I think Bayonetta (1 or 2? Can't remember) was the biggest pile of garbage he put together. Painful, absolute lack of awareness and thinking for himself. This happens when there is no chat to handhold an adult, the "average gamer".
More like the worst generation of gamers who is responsible for some dumbed-down games these days despite the fact he experienced the old school era of hard videas. How does this even work?! Wasn't there the rumor he is the reason Half Life invented automated crouch jump?
However, at least playthroughs like them had comedic value, just undisturbed Phil, failing on his own by trying to think for himself. Now chat ruins everything.
Edit: Forget Bayonetta. Duck Tales it is! Annoying insult throwing clown mode for "special kids". A playthrough which is so bad it would convince a higher alien race to wipe out mankind for our own good.
Phil uploaded that and thought it was good. I just can't. I could give him the benefit of the doubt if this was one of his earlies and he lacked experience and knowledge, but it was not. It was not...