Anti-Climax Boss: For the second game, you finally gained entry to the forbidden Island CX. You fight your way through the island fortress to the emperor who has been hyped up to be a major Big Bad of the game...only to realize he doesn't have an actual Boss Battle and takes only a single (or two) hits before succumbing to a Plotline Death to pull the lever that starts up the Emerald Moon Reactor.
Funfrock, the true Big Bad of the game, can end up as this in the final battle if the player chooses to use the Ring of Lightning. Yes, it DOES indeed one-hit-ko the final boss of the game.
Awesome Music: Both Relentless and Twinsen's Odyssey have really nice and memorable soundtracks.
Disappointing Last Level: The final area you fight through in Relentless. Not so much the final confrontation with Funfrock, but the path leading up to it after destroying the cloning facility is pretty dull. It's just a long boring mining road which includes one particular rage enducing point where you have to get by an invulnerable Dirt Excavator enemy with absolutely no room to work with.
Fanon: A vast majority of people believe that The Voice Twinsen hears when he grabs the Wannie Key Fragment is the true Dark Monk of Zeelich.
The Ring of Lightning in the second game when used as a weapon is so overpowered it can One-Hit Kill the final boss of the game.
The Protection Spell is just as overpowered if you choose to grab it from it's Bonus Dungeon. If your quick enough at killing your enemies, you could possibly complete the game without ever taking any damage if you always keep your mana up.
Aggressive stance with the sword. Never miss a swing and you basically have your enemy stun-locked.
The final grueling walk down the mining road before confronting Funfrock in Relentless. The Dirt Excavator that is almost impossible to bypass gets on almost everyone's nerves.
On the topic of the original game, The Temple of Bu walkthrough can really tick people off due to the feeling of Check Point Starvation. People are forced to complete entire sections of the temple without the ability to save part way through, and will end up losing all their hard work going through the temple layouts if they die. Switching between the temple's layouts is the only way to save the work going through the temple.
The Island of the Volcano, with lava galore in Twinsen's Odyssey. Thankfully, it is only optional.
Tier-Induced Scrappy: Sword combat actually has 4 distinct types of gameplay connected to Twinsen's 4 mood stances. However, the aggressive stance is the only mood players ever rely on and is ''quite'' overpowered if the player never misses a swing; leaving the other 3 sword moods in the dust. The lone exception being the sporty stance when people wanna fool around with its front-flip attack which is Twinsen's most powerful sword swing which doesn't offer much since you can pull off the same damage, if not MORE, in the same amount of time with the aggressive stance.