Tyler tells the story of how he never got past the first star as a kid because he couldn't figure out how to defeat the Big Bob-Omb. His dad tried and couldn't beat it either, causing them to sell their N64.
Josh: Wow, so you come from a family of idiots.
On one level, Josh has to fly around with the Wing Cap to gather 8 Red Coins. As soon as he gets the last two, the cap immediately goes away, sending him plummeting to his death.
Josh: (After noticing that his cap was disappearing) Oh shit! Oh shit! Oh shit! Oh shit! OH SHIT!
While in Jolly Roger Bay, Tyler expresses his dislike for the level, and underwater levels in general. The game immediately retaliates by having Tyler glitch straight through the hull of the sunken ship.
When Josh dies after getting all eight red coins on the first bowser level, the triumphant return of an old joke
Josh has trouble in Bowser's Dark World, while Tyler breezes through it and moves onto Big Boo's Haunt. Josh, having previously stated that Tyler would not get ahead of him this episode, starts lying and saying he was joking about having trouble and is really far ahead of Tyler. Tyler half-believes him until he tells Josh to tell him the exact name of the level he's on. Josh, who's still fighting Bowser, can't do it.
And then when Josh finally gets to Big Boo's Haunt, he has trouble in the first level, where he's supposed to kill all the Boos:
Josh: (calmly) Tyler, can you help me?
Josh: (calmly) So...uh...on the first mission of Big Boo's Haunt...um... (suddenly yelling) WHERE THE FUCK ARE THE GHOSTS?!
Tyler mentions how someone has actually made an "Atting Tunens" parody channel and said that if the real AttackingTucans wanted it, to message him...but he intentionally mispelled 'message' as 'massage', which Tyler interprets exactly how you'd expect.
In quite a similar fashion, after the "Josh is a clam"-short was released, someone made a "Josh Clamson"-parody channel, with the exact same conditions as the "Atting Tunens"-channel.
Also incorporating Josh getting enraged that Tyler ignored his hint about where to find more coins for the 100-coin star in Jolly Roger Bay due to misunderstanding what he meant.
Then there's the Tyler is Barney animation, which takes a pretty normal context and turns it into something horrifically hilarious.
In Episode 5, Tyler has a lot of trouble on the second mission of Lethal Lava Land (the one where you have to defeat the three bullies). This allows Josh to catch up and he beats the same mission in under a minute. Tyler's reaction is priceless.
At the start of episode 8, Josh and Tyler get the hundred coins of one world, then Tyler goes to Snowman's Land, and is so used to doing it that he reflexively starts chasing after every coin in that world before realising what he's doing.
Tyler's phone rings and he jokes that it's Josh, then they discuss that one of them phoning the other in the middle of the Versus would be a good trick to put them off...a few minutes later, Tyler actually does it to Josh.
Tyler's Epic Fail at getting the 100 coins in Snowman's Land, resulting in him having to restart the level three separate times. The first two times, he loses the koopa shell, which he needed to get inside the igloo. The third time, he makes it into the igloo...and gets stuck there.
Some of the strange things Tyler says in episode 9.
Tyler: (looking at the purple and circular Chuck-ya) It's the grape. Bye grape. (Starts glitching on the platform) OHHHH!!!!'
Tyler ends up talking about he should have a child and goes on to list several good traits that child would have. Then he states that he would raise the child to assassinate Josh and then get rid of it.
Josh: See, this is why you're not allowed to have children!