These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Bowdlerise: "Killer" was renamed as "Evil" in America for predictable (though nonetheless practical) reasons. "Basalt Horogium" was renamed to "Twisted Tempo" by Nelvana and Hasbro for unknown reasons, while Giraffe was replaced with Zurafa. Additionally, Masamune's Ray Unicorn is now "Ray Striker", even though a unicorn is clearly portrayed on the face bolt. Then there's Gravity Perseus, which was given the horribly generic name of Gravity "Destroyer". It doesn't help that the episode it appears in clearly references "Perseus", the hero from Greek legend who slew Medusanote As in the gorgon with snakes for hair who turned anyone who looked at her into stone.
Cargo Ship / Foe Yay: Daidouji and cacti. Says he hates them, but keeps a bunch of them in his office.
A gang of bullies are going around tormenting younger and inexperienced bladers. One of those bladers just happens a cute kid around the age of 10. One of the heroes enter the town and tries to defend the cute kid.
All Rock Scorpio's Deadly Poison does is replaces Kyoya with Busijima, has Sora take Kenta's role, with Kenta himself taking Gingka's role (Gingka still appears, but not in the major role he did in Pegasus and Leone).
So Bad, It's Good: The whole voice acting and emoting in the English dub. Especially the laughably bad translations and strained expressions.
Traumatic Vocal Evolution: Notice how Benkei's voice is much deeper, cooler, and menacing in the first episode of the dub? Following his self-induced Groin Attack in episode 2 by falling on a steel girder, it changes into that squeaker, goofy, and grating voice we're used to hearing. Guess he did some permanent damage to his boys with that one. Fridge Horror, anyone?
That One Attack: In the Metal Masters DS game, Lightning Sword Flash and Gemios Downburst with insane priority and spammable on top of everything. That One Attack on the receiving end, Game Breaker on the dishing end.
That One Boss: The DS games have them in Van for Metal Fusion and Agito for Metal Masters. Van's Belzebrute has insane Stamina and Dark Stream as a special move, which is an instant Crash Out thus giving him 3 points out of 4 needed to win, so if he uses it and has even if one win against you, game over. Agito's Nightmare Rex has insane range with King's Roar, a shockwave with range only rivaled by Capricorn's Sniper Shot, which will most likely wittle your bey's stamina down with constant hits unless you can either get out of its range or hit Nightmare Rex as it readies the move. And even closing in isn't a 100% safe strategy as Agito can still hit you with Nova Strike. And god help you if you're playing with Mei-Mei, Hikaru or Ryutaro.
Viewer Gender Confusion: Though nobody gets mistaken for a girl in the series, Ryuutaro, Teru and Jack all have some very feminine looks. And Tsubasa's first appearance was complete with the sparkles that are usually reserved for pretty girls.
It's to the point that almost every other dude has feminine looks, particularly long hair and bared midriffs. A lot of them look more like women then the actual women.
The Woobie: Many characters have at least one moment like this. Mainly, Ginga after we find out about his backstory.
Also Tsubasa. Poor, poor Tsubasa...
Woolseyism: Watarigani's Cancer Beyblade (named for the constellation that resembles a crab) was renamed "Gasher" in the North American franchise, probably so people wouldn't think of the "other" kind of "cancer" (especially since Watarigani is a rival)...