Ending Fatigue: The very last challenge from Game Master Arino involves reaching the ending screen of every game (just like in the show!). While the cheat codes give you some slack in some games (a hidden NPC allows you to warp to the credits of Guadia Quest, a hidden warp in Cosmic Gate instantly teleports you to Stage 64), this means you have to beat Rally King effectively twice (original and SP)... and finishing in first place in all four races, which is an incredibly difficult endeavor unless you use the "No opponents" cheat, turning it into a 20-minute drive. Also, you have to beat Star Prince and Haggle Man 1 and 2 twice too, as all three demand you to beat a second loop to see the ending a la Ghosts N' Goblins, which is aggravating considering you already "beat" Haggle Man 2 as part of a challenge. Oh, and if you made the mistake of having already beaten a game you liked in Freeplay Mode, it didn't count.
Ho Yay: Young Arino can ask the player whether or not s/he is single (this can happen for either gender).
Sequelitis: GameCenter CX 3 is less well received due to the change in developers. Particular criticisms include the downgraded quality of the games as well as the change to to simplistic 2D characters in the overworld.
No Problem with Licensed Games: Granted, it's loosely based off of the show, but it's a really good experience, especially if you know Japanese, play that version, and know all of the references to the show's running gags and memorable moments.
That One Level: Beating the Dungeon of Darkness in Guadia Quest. It's such a lengthy and daunting undertaking that many people wind up giving up and never unlocking Haggle Man 3.
Woolseyism: The Japanese version, Arino's Challenge, contains several in-jokes towards Japanese gaming culture (including the title, a jab at Takeshi's Challenge, which was one of the worst games played by Arino on the actual TV show). Naturally, these were converted to western in-jokes in Retro Game Challenge, such as the fictional GameFan Magazine going from a Famitsu parody to an EGM one. Some are fine with, some are really upset that most of the references to the show are gone.
Rally King series
Breather Level: The third challenge Game Master Arino gives for SP is to get a turbo when a race begins. Amusingly, both he and young Arino comment positively on the great effort he's doing for the challenges. Then he admits how pathetic it was after you're done.
Padding: SP is essentially the same game. At least the challenges are different.
Guadia Quest
Game-Breaker: Dormi, the sleep spell, absolutely eviscerates the game. It can turn many fights into a foregone victory and heavily tips the scales in your favour when it doesn't.
Goddamned Bats: There's three kinds, and they're all birds. The red birds fly down to your level and hover just outside the range of your shurikens, before charging at you. Black birds fly down and immediately careen towards you. Brown birds fly in the same wavy pattern as Castlevania's Medusa Heads. Oh, and guess what? All three varieties appear nonstop in the most hazardous parts of the levels, especially the red and black ones. Admittedly, their appearance is telegraphed by a sound effect, but they almost always show up when you're in the middle of a jump or otherwise don't have room to maneuver.
Probably invoked, as when it comes to games Arino is known for having a "bird phobia", making it one of the many nods to the show.
Padding: One of the challenges is to get the 3-shot. The challenge after that requires you to destroy something that requires the 3-shot...but it didn't save your progress. This happens again after that challenge. Fortunately, the final challenge doesn't require you to buy it again.
Wiz-Man
That One Level: The final level is much harder than any of the preceeding levels. This is mostly due to the final boss, which shoots magic shots in the 4 cardinal directions that freeze you in place (compared to the other wizard enemies in the game, who only slow you down to various degrees) and remove your currently-used rod, making you easy prey to the other enemies. It's also extremely easy for his shots to stunlock you completely if he decides to teleport towards you after connecting with one of his shots, making it extremely difficult to not die afterwards. What's more, the requirement to get the golden rod to appear is ridiculously specific (collect exactly 25 red and blue crystals each), and you only get one chance to get one per continue. The above might be at least somewhat bearable, but there's also purple knights that can only be killed with the golden rod, and in order to truly beat the game you first need to kill the final boss instead of just taking the level exit when you've collected all the crystals; trying to do so just sends you back to the final level to try again. Killing the boss is also an exercise in frustration, since he takes three hits and attacks so quickly that you get frozen 90% of the time if you try to attack him between his shots even if you manage to land a hit on him, and he also teleports quickly after his second shot. Finally, if you take too long to finish the level, and it's practically guaranteed that you will, the game also starts spawning white wizards, who attack as quickly as the final boss and slow you down to a crawl and remove your rod if they hit you. And even if you manage to kill the boss, you need to finish the level the normal way for it to count.
