You really have to watch each episode two or three times in order to pick up on the subplots, subtext and foreshadowing that become important later.
The Symbiote seems to have two voices, one from the original person, and a second, much darker and more violent voice. The brilliance comes in when you realize it's the same actor as the person wearing it doing the voice each time, to represent that the Symbiote is bringing out the worst aspects of the person it's currently being worn by.
In the beginning of the show, why did Peter have a crush on Sally Avril? Because she bears a slight resemblance to the one he later comes to love the most: Gwen Stacy.
Throughout the show, Peter carries around a brown bag (which he keeps both Peter's and Spidey's supplies in). That style of bag is called a newsboy bag... and Peter's part-time job is at a newspaper. Probably unintentional, but a fun detail nonetheless.
In the dance episode, Harry can be seen in the background applauding Mary Jane for winning queen. At the same time, the Green Goblin was battling Spider-Man. A nice little bit of foreshadowing.
In Rhino's debut episode, Spider-Man points out his one weakness; that his suit is so well insulated it overheats with ease, and needs cooling down regularly; this is actually a problem real-life rhinos have, and they need to refresh/cool down themselves with water or fresh mud, or rest under a tree's shadow, when weather is too hot. Also, in subsequent episodes, Rhino rarely fights on day-time; he fights at night, or when weather is cool enough.
Possibly a coincidence, but Spider-Man's first fight with Doc Ock happened to be in episode number 8.
During its fight with the Sinister Six, why did the Symbiote only attempt to kill Dr. Octopus? Because The Doctor had threatened to "peel it away," subtly foreshadowing how clingy it really is to Peter.
Venom mocks Peter for thinking he could freeze the symbiote to death. In hindsight, it didn't have any problems surviving in the cold vacuum of space, so it makes sense that a deep-freeze wouldn't have affected it much.
Season 2's twist of Norman being the Green Goblin is set up remarkably well: in Season 1, during the scene where Chameleon is posing as him, and he hears that a thief has broken in, he asks, "A thief!? What did he steal?" putting emphasis on the "he". It's like he's implying that he's a different thief. And then, when the Goblin spots the faker, he pulls the briefest of double-takes. In addition, in the previous episode, the Green Goblin triggers Doctor Octavius's transformation by pulling out the safety key to engage the experiment. Norman Osborn then arrives and shuts off the experiment by inserting the same key. You know, the one the Green Goblin just stole.
Mary Jane knows Peter is Spider-Man, much like the Parallel Lives story (Word of God confirms she figured it out before they met). Of all of Peter's friends, MJ is the only one who takes his excuses at face value, she willingly stays back to save Peter the last dance as if she's expecting him to show up and she warns Peter about Eddie Brock's behaviour. She's also among the most supportive of his friends and his biggest defender whenever someone's mad at him (usually due to Spidey stuff).
At first, Doctor Octopus telling Aunt May and Anna to step aside before he and the Sinister Six begin fighting Spider-Man in Group Therapy just seems part of his pragmatic, soft-spoken villainy - no more casualties than need be, especially someone he has no quarrel with. But then one remembers, in the comics, Otto was a huge Mama's Boy, and his mother frequently protected him from his abusive father. Otto probably has a soft spot for little old ladies that remind him of her.
Also a bit of a wink towards the original comics, where he tried to marry Aunt May.
Peter mistaking the Osborn wine cellar for a secret room makes complete sense, since he's too young to drink and Norman had no reason to tell anyone outside the family about the secret entrance to the cellar.
The Master Planner's strategy for the Sinister Six's second attempt to take on Spidey was well thought out and learned from the mistakes of the first time. When the Six fought Spider-Man the first time, he was able to take several of them out with either friendly fire or using their own abilities against the others. Meanwhile, the second time had the Sinister Six split up into pairs who fought Peter two at a time, with abilities to complement the other (Pairing Vulture with Electro ensured there was minimal chances of Vulture getting caught in collateral damage from Electro's lightning unless Max was deliberately aiming for him (which of course is what ended up happening courtesy of Spidey), Rhino and Sandman already worked together, plus they could only do physical-based attacks that wouldn't do any meaningful damage to the other, while Kraven's heightened senses could see through most of Mysterio's illusions and ensure that Spidey couldn't use those to trick him) while simultaneously marathoning the fight to wear Spider-Man down and tire him out. It obviously didn't work, but points for the effort.
One thing of note is that Spider-Man would likely not effectively able to combat all six at once at either point. The first sin 6 fight actually had Spider-Man retreat even while wearing the suit. The second attack from group therapy failed because Spider-Man had more advantages than he did the first time.
Spider-Man was using the black suit, although this was true for the first time
there were no civilians to worry about
Most importantly, Sin 6 weren’t used to working like a team. They all attacked one at a time without working to well with the others in mind. There were too many moving parts which led to people getting in other peoples’ way (especially rhino) and lots of friendly fire. The only ones who worked well together were shocker and electro who were just filling the same function. Despite that, Spider-Man still had a lot of trouble.
The second time the Sin six got their act together and trained to work in conjunction with each other. They only went with teams of 2 with good synergy to avoid friendly fire shenanigans like the last fight, so Spider-Man had to really think smart to take them down. Even then, most of those fights were only won due to fighting location being in Spider-Man’s favor.
How Spider-Man catches Mysterio in "Reinforcement". In real life, many spider species have poor eyesight, and can't easily see when something is caught in their webs. So they look for deformities in the web to let them know that prey has been caught, and strike at the deformity. In this episode, this is what Spider-Man does to capture the invisible Mysterio; he coats the entire department store floor in a massive web, then looks for the deformity/irregularity in the webbing to find and catch Mysterio.
The three New York City crime bosses who we get to know over the show, actively follow their own philosophies for how to manage New York City's crime, which also lead to their defeats.
Tombstone treats everything like a business. With middle managers and layers of separation between him and the actual action, it allows him to offer you both as a criminal mastermind, as well as a figure in the public eye. When Spider-Man arrives on the scene, at first he doesn't believe it and it's only willing to act once he begins cutting into tombstones income. Then, he attempts to remove Spider-Man, through the use of the enforcers and supervillains, and when that fails he attempts to buy Spider-Man out. When this fails, he goes back to the strategy of keeping Spider-Man busy through simply creating new super villains for him to fight. However, this creates his own undoing, As he tends to cut loose those who are no longer profitable for his operations, allowing Doc Ock to set up his own criminal Empire, and creating multiple freelance villains, such as Rhino and Sandman, who aren’t there to help him in his moment of need. The Business practices he employs also alienates Hammerhead at a key moment, leading to his betrayal and Tombstone falling from power.
Doc Ock employs two primary philosophies when managing his own criminal Empire. He believes in the law of the jungle, as well as the scientific method. Doc Ock's creation of the Sinister Six, both iterations, shows the progression of using the scientific method in order to try and figure out how to defeat Spider-Man. Employing new tactics, reinforced equipment which is no longer vulnerable to previous weaknesses, and even new members who are better equipped to handle Spider-Man skills. All the same, Doc Ock is also an opportunist who will exploit any situation to get an advantage. Such as playing off rhinos emotions to get him to destroy the hard drive, or attacking a seemingly weak Silvio Manfredi. In turn, this leads to Doc Ock's defeat. He is not actually physically strong himself, and when cut off from his resources, or an unexpected play enters the game, such as was done through the Green Goblin's own version of hammerhead, his plans fall apart. He may have prevailed over this, however his belief in the law of the Jungle meant that he attacked Sylvia Manfredi, when the two of them easily could have beaten the trap together.
Finally, Silvio Manfredi is an old-school gangster, with a strong belief in running things through the family. This is shown through his exclusive use of Silver Sable, his own daughter, as his primary means of acting while not present. This old school method of acting is clearly shown in his hydraulic-powered battle suit. Clearly not as advanced as the other supervillains weapons, it's something that he is shown clearly being very familiar with and using with exceptional skill. However, it's also something which Spider-Man and Doc Ock can quickly spot weaknesses in, and begin to dismantle, leaving him helpless. His family philosophy quickly runs into trouble, when Silver Sable is taken out by Hammerhead at the meeting. This direct threat to his daughter immediately has Silvermane fly into what amounts to a frenzy, and attempt to kill Tombstone. Silvermane reacted violently to his daughter being threatened, and because of his over-reliance on family, has nobody that he can really call for help from, unlike the other two. However, his reputation also allows him to command respect even after being in prison for years, and when there is an attempted breakout at the Maximum Security Prison, he's quickly able to rally powerful group of prisoners together, simply through his experience and reputation. Silvermane's reliance on what he's familiar with and his family left him high and dry at a critical moment, but also as clearly served him well in the past.
Flash's disbelief that Eddie is Venom seems like an example of him being Book Dumb, but it actually makes sense as it's based on the same reasoning that Captain Stacy used, body types. Captain Stacy realized that Chameleon wasn't Spider-Man because he was larger than him. As Flash notes Venom is twice as big as Eddie, thus it's not likely he's Venom. Given the symbiote has a sort of Sizeshifter effect on Eddie, a fact Flash doesn't know about, it's a logical theory.
There no way in heck Norman would've had the foresight to frame Harry for the limping leg thing, considering he just stumbled upon the passed-out form of his son after his bout with Spidey in the first season finale. Plus exactly what reason did he have to fake a limp in the first place?
Spider-Man had already accused the Goblin of being Norman. If Gobby had a limp and Norman didn't, it'd throw Spidey off that trail even if he didn't come across a convenient scapegoat.
I don't think crippling Harry was part of a plan. he does describe it as "serendipity"
Part fridge logic and maybe Fridge Horror; Rhinos suit. So, it covers his entire body in a metallic armour, to the point where the only exposed bit of skin is his face and he can only sweat through his face. How does he use the toilet?
He probably has some sort of tube for that.
The comics establish that he has a flap for that.
After curb-stomping Peter in their first battle, Venom declares his intent to attack everyone Peter cares about. His initial target is Aunt May. Peter arrives just in time and fights ferociously, even scoring a few good hits. Still, Venom could've definitely beaten him, but instead decides to reveal his identity as Eddie Brock and go after the person Peter loves the most - Gwen. This makes perfect sense: Eddie wasn't actually trying to kill May and was just toying with Peter, especially since he knew Peter would think of her as the first target. A few episodes earlier, he even says that he "still remembers what a great lady she is". Even if the symbiote was holding a grudge against May, which it has no reason to, Eddie wouldn't allow it to harm her. Might be a case of Even Evil Has Standards.
Also, everyone knew that May was in the hospital due to a heart attack, but only a few people (namely Peter and his friends at school) knew that she was doing better. Eddie might have thought that May was still fairly sick and close to death, which would make attacking her pointless.
Spidey using lockers to create a ringing sound that would disrupt Venom... yeah, try hitting a locker with a baseball bat. They don't work like bells, they'd get dented and make a loud, non-ringing sound for less than a second. Artistic License – Physics is pretty much the only way this could work.
It probably helps that Spidey has super strength and therefore hits much harder than a normal person.
It's not the strength that matters, it's the object that's being hit, specifically its shape and the material it's made of.
If the gene cleanser didn’t work on Colonel Jupiter, then why would it work on Venom? Dr Connors mentioned that when John got infected by the symbiote spores, he tried to use the cleanser on him to cure John, but it didn’t work. But when Spidey uses it on Eddie later on, it somehow works? Why? Eddie and John both derived their powers from the symbiote, so if one’s immune, the other should be too.
The symbiote and the spores are two different entities, the spores just attached themselves to the life form
the spores are multiple organisms, which needed to be killed collectively and completely to keep them from reproducing again. That’s why Dr. Connors had limited success with electricity but Spider-Man succeeded. Spider-Man gave it enough amps that all the spores died and none were spared. The Connors likely did not use so much power for safety reasons so the spores were able to reproduce again.
, Harry can be seen in the background applauding Mary Jane for winning queen. At the same time, the Green Goblin was battling Spider-Man. A nice little bit of foreshadowing.