In the Ghosts 'n Goblins playthroughs, when Arino first meets the Red Arremer he runs away, losing a life but skipping the demon by reaching a checkpoint. It's very satisfying to see him getting over his fear and carefully taking down the Arremers when forced to fight them in the end-game.
Despite having some trouble with stages 2 and 4, Arinoppa the Rapper beat Parappa The Rapper in just about 4 hours.
Any time Arino finishes a game on a 24-hour or less live events.
His victory on his third attempt at Pilotwings was truly miraculous. On his last try and with little time left, he had finally finished off all the enemy turrets on the last level. Under immense pressure, he still had to land the helicopter successfully, which he does, right as the game started complaining he was descending too fast!
Arino finishing Ninja Spirit in a mere 2 hours, largely thanks to pure luck getting him through an extremely difficult Free-Fall Fight which took the ADs 5 hours to do the same.
The AD's have their own Crowning Moments of Awesome, including...
Inoko MAX, having spent most of the fifth season screwing up in one way or another, redeems himself in the finale by getting the good ending of "Shadow Land". Much later, in Season 16, he gets another when Arino bets on him in Barcode Battle and he wins.
Though not an AD, sound guy Fukuawa volunteered to attempt the good ending of Densha de Go!! by playing the Yamanote Line without continuing. None of the staff thought he could do it, especially since it was his first time ever playing the game. He completed it in six hours.
The latter half of the Super Mario Bros 30th Anniversary Special at Nico Nico Chokaigi 2015 involved various Japanese Let's Players trying their hands at Super Mario Maker levels made by Arino. After 1 win and 1 loss, they brought in a special tiebreaker guest: Shigeru Miyamoto himself.
The Budokan event is one for the entire show as the sheer scale of the people who attended was huge (we're talking about 7000 people who went there just to watch a middle-aged old man play retro games, something no Let's Player can even claim to have). Though the Chief himself had some really awesome moments (especially clearing Mario 8-4 with the hammiest announcement ever), the crown has to go towards AD Matsui for getting towards 8-4 with 20 lives and fire flower equipped Mario in such a short time before the event starts.note The Famicom console that had the well equipped Mario froze so he had to do it all over again
Arino played a fair bit of Super Mario 64 with a hatless Mario, which causes the player to suffer double the normal amount of damage when hit.
When Arino found out a female staffer beat Wizards and Warriors in roughly six hours for said game's challenge, Arino decided to one-up her and beat the game faster than her time, which he manages to succeed with a time of 4 hours and 50 minutes.
Then there's the fact said female staffer's only knowledge of video games comes from smartphone games she plays to pass the time. For someone as inexperienced as her to beat Wizards And Warriors in just six hours is nothing short of a miracle.