Other mistake: In the opening sequence, Dr. Wily's name is misspelled Dr. Willy with two L's. This mistake is carried over to Mega Man Legacy Collection 2.
Audio problem: If it is raining, like in the Halloween event or other random storms in the game's time cycle, the audio can change in structures you're inside. But the rain follows the rules as well, like if you're in a tunnel, the rain doesn't fall inside the tunnel. However, if you get inside a bus that is in that tunnel, suddenly you'll hear the sound of rain hitting the roof of the bus, despite there not being any rain that can hit it.
Audio problem: Several lines in this game are said where the character's mouth is out of sync for at least a third of the line. Especially Doc's lines.
Plot hole: Level Five: After finishing the mission to defeat The Dirty Bubble atop the Sea Needle, the game completes, the Dirty Bubble is stopped and Bikini Bottom is saved from the little dirty bubbles infecting them. After saving the day, the game lets you go back to Bikini Bottom to finish off some other missions, but despite this the citizens are still infected by the little dirty bubbles and if you go back to the Sea Needle, the Dirty Bubble is still waiting there and reading to be battled again.
Bug: If an NPC zombie is too close to certain obstacles, they will appear to be crouched on the ground. The Collision is just enough to cause them to not be able to make any sideways movement unless they are activated, thus they will just be crouched on the ground slowly rotating around. It is comical for a group of zombies to be doing this while occupying the same space, as they have a dog pile effect making a tower of crouched rotating zombies.
Other mistake: When Set takes control of a robot, he uses it to grab and pick up Frau Engel by her face causing damage. When Frau Engel stands up and looks directly at Blazkowicz, her bottom jaw is dislocated and most of her lips have been torn off, making talking impossible. But, when she threatens Blazkowicz, she is speaking in completely coherent sentences.
Bug: A game-breaking glitch can commonly occur during the prologue, upon creating a second character. *Spoiler* After the cryogenic chamber cutscene, after being released from the chamber, you will be stuck, unable to move or use any control except for Pause. The only known fix is to turn the entire game off and then go through the cutscene again.
Other mistake: Every time you retrieve a part of Dracula, the message on screen misspells the word "Possess", giving you messages such as "you now prossess Dracula's rib."
Bug: Most notably with the M4, often times an assault rifle will be stuck unable to fire. It will act like I is firing, but just be recoiling with no bullets coming out nor the ammo count going down. You must switch weapons, then switch back to the assault rifle, then change it from semi automatic and then back to fully automatic to fix it so it can start firing again.
Other mistake: It is possible to check the vitals on Polus. This would involve attaching some kind of medical device to allow this. But Imposters are shapeshifting aliens that are not supposed to be there, but their vitals are readable as well. This should not be the case.
Suggested correction: Given that the players have backpacks and we never see the back there could be a vitals reader on the back.
With a recent update, it's now clear that there're no vitals reader on the back.
Bug: In this game, unlike the sequels, the CPU players will go after any item that spawns with reckless abandon. If there are just two level 9 CPU players on the stage, and an item spawns, they will both go for it. If they are equal or approximately equal distance from it on opposite sides, they will steadily walk towards it. Once they get within a certain distance of each other, their Level 9 defense programming kicks in, and they will shield roll past each other, and the item. Get up, and do it again, and again, and again bringing the fight to a standstill until the item fades away.
Continuity mistake: Before the cut scene where the American is in an outhouse, if the American dies in the night before, he will still be shown in the cut scene despite being dead. Similar happens in the cut scene of the American and German asking the Russian where he got the meat that's in the food he just made. All 3 survivors are in the cut scene, even if you had 2 of them die that night.
Continuity mistake: In the level Second Sun, when you take control of Ramirez for the second time, the EMP doesn't hit until a few seconds pass. You can tell because the street lights and helicopters are still fully functioning. However, your holographic sight has already been disabled.
Continuity mistake: In the original Xbox version, after retrieving Jagger Valance's package and giving it to him, he tells you how to escape from Butcher Bay. After he does, kill him. Later in the game, after making it to the Space Port, a ship will be there waiting. When entering the ship, Jagger Valance will be there attempting to open the door to the cockpit.
Character mistake: When Fatman begins to explain the 'party' rules, he says "If you prefer to stay in ONCE piece..." This is a spelling error, as he should have said 'ONE piece'.
Bug: Not sure if this can be done on today's consoles but, this could actually be accomplished on the original NES. Two controllers must be plugged into the NES. Take a heavy item [i.e. A book or stapler.] and place it on the right directional button on the second controller and keep it there. Next, fall into a pit and wait for an enemy to go over the pit. When this happens, Megaman's energy will be completely depleted. After that happens, press the jump button on the first controller and Megaman will jump out of the pit and will now be invincible throughout the rest of the level as long as the right directional controller on the second stays pressed down. Note: this will only work when playing the first part of the game which involves Dr. Wily's minions but, won't work when the player makes it to Dr. Wily's lair.
Continuity mistake: Smithers is shown in Bart's Nightmare with green hair, instead of the grey hair he is usually seen with in the show.
Factual error: On the Solar level, the other Star Fox team members only take damage from heat while they are talking. Being on the Lylat System star, they would be constantly taking heat damage just like Fox.
Other mistake: Kaiser-Friedrich Museum: At the beginning on the bridge you see several Russian soldiers. The ones just walking idly about on the bridge seem to be blind idiots. They just run into things causing collision and so, they just stand there walking in place against obstacle. Sometimes they turn a bit and keep walking until they hit the next obstacle.