Egocentric: After his rise in popularity, everything became more "about him" than about theories. 80% of the videos have his face photoshoped in for no reason, he reminds everyone all the time how it's HIS show, how that was HIS JOKE, how that joke he just did WAS AWESOME, etc.
He is "special": Mat for some unknown reason thinks he is some kind of "embassador of gaming culture". The way he talks in the pope video, makes him look like some messianic figure that is showing the world that videogames are changing the world for better and gamers are heroes. In reality he is just some dude on youtube who makes clickbait videos.
Hipocrisy: Matpat went to the pope to ask how to deal with haters but mat is a grauitous asshole in ALL of his videos. For absolutely no reason he will take jabs at series, be misogynist, etc. Any Zelda video will talk shit on skyward sword. The DOA video says that "woman are worst than men because decades of cience says so" (shows no source at all) and "Do women even play dead or alive?". Says Ace Attorney is "that series that everybody knows the meme but nobody plays", etc. He acts like a poor victim but loves to talk crap about the game he is theorizing.
Bullshit theories: He pratically "jumped the shark" after the fnaf spam, most theories he does nowarays are awful, not even in the "it's kinda silly" but in the "obviously nonsensical bullshit". "Link is dead!", "Wario is 10 feet tall!" , "Sans is Ness!", "Scott is wrong about his game!". Many of them became memes/ironic shitposts. His last theory is probably one of his worst yet:
In this video Mat says "Phoenix is a criminal because he hid the evidence!", but he fails hard because:
1- Phoenix didn't hid the evidence. The detective found it and got maya arrested.
It shows right there in the video.
2- Everybody in the game hides evidence all the time. The game doesn't play by real life laws.
3- The game explains how evidence works on case 5, but none of this is mentioned so it's safe to assume MAT DIDN'T EVEN FINISH THE GAME.
But it doesn't matter because he ends the videos with " But it's just a theory! A game theory!" therefore he shields himself against any criticism and let his fans will defend him.
Sellout: Matpat makes a lot of sponsored theories but doesn't mention it. He did a theory about MMORPGs dying while promoting another mmorpg. He did a theory about master chief armor that was sponsored my microsoft etc. But the worst of all is that mat sold out to youtube red to make his new show "Game Lab". That wouldn't be so bad by itself by Matpat was salty that Jimmy Fallon had move views than him and said "youtube is about the community, you can't make youtube tv!"
And yet, he joins youtube red (supposed to be like tv) and makes a money exclusive videos, and later defends it because "you gotta support the youtube community blabla". He changed his mind for the money. He puts much more effort in his new show than his old show, he doesn't give a fuck about the community that made him popular in the first place.