Inside the Alchemax building, Spidey and the Ms. are joined by She-Hulk and Spiderman 2099. Start by smashing everything (always a strong Plan A). Pay special attention the the glowing yellow Alchemax logos- smashing them all nets you a prize.
When ready, draw close to the large glass window to trigger a proto-symbiote attack.
Fighting symbiotes is kind of fun- when you defeat their host, they'll appear as blobby, cuttlefishy things. Smash them with ground-pound attacks. If you miss, they'll zip around the floor as malevolent little puddles, and try to take over you or your teammates. This can give you an excuse to beat up your own squad, and once the symbiote is knocked free, the cycle repeats. That said, you can also just ignore them if you choose- one zombified team member is rarely a real problem. When ready, pull down the red handled panel in the room where the scientists were.
This reveals a lazer maze. Hack it with Kamala to open up a sideroom.
Step inside to trigger another three-symbiote attack.
Smash them , and then press the button inside this room to reveal a new console, and a giant hexagonal keypad.
Let it be a moment, and instead have anyone but She Hulk grapple the vent above the sideroom.
This will pull down a glass canister. Use Gwen's drumming to smash it for a minikit.
Now use that new console. Pressing the left and right arrows cycles through images. Keep going until you find the hexagonal one.
Step on the hexes indicated onscreen to open the door.
This automatically moves your heroes into the reactor room. Stomp a few more symbiotes (they are the headline act here, I suppose), then use Gwen to smash the glass panel stage left.
The room beyond is full of radioactive goo, but it's just bubble bath to She Hulk. Wade in and smash the blue pieces to form a push-handle. Push it to fill an energy meter on the right side of the room.
The push handle on the other side is already built. Fill that meter too to unlock the nearby ladder (the camera will point it out to you).
Still as Shulkie, take the ladder up, and pull open the door there.
Switch to a techier teammate to operate the console here. No strategy required, just keep holding [LEFT] until the glowing ball has fallen down all three levels, and into the reactor.
This opens up a new area in the stage right side of the level. Enter this area and IMMEDIATELY hit the switch by the dual laser. If you don't do it first, it may become bugged, and force you to replay the level.
With that out of the way, have Gwen or Kamala enter the marvel vent in the left of this room.
Up top, hang from the wall-lever to deactivate the electro-spitters below.
With the path cleared, have another character push the giant block along the slidey tiles.
At the end of the tiles, an elevator takes the block up. Have whoever's hanging from the level detach and push the block all the way left (the laser has mysteriously retreated).
You'll have to deal with a Kangbot assault as you pass the glass window, but they're way wimpier than the symbiotes. Bust 'em up, then finish your block sliding to release the second core. As before, use the console on the upper level stage left to guide the energy-ball down the three reactor levels. This opens the main door, and triggers an attack by stronger Kangbots- giant spiders and ninjas among them.
You can use webs to safely take out the spider-bots from a distance, or you can just use Kamala to smash everything that moves.
Either way, proceed through the main doors when ready for the final boss fight, against Carnom.
You'll spend most of the fight running around the level, smashing goons and webbing up Carnom, but do note the marvel vent here, which you can duck down for a quick minikit.
Fighting Carnom is pretty straigthforward- webs are the safest way to reduce his health, though you might risk a few hit-and-run punches just to speed things along. When he reaches half health and one-quarter health he'll leap to the ceiling and ring like a bell, summoning more goons, but nothing you have fought a couple times in this level alone.
When you get him to zero health, he'll reform into a sort of vomiting dinosaur.
Use the central pillar to evade his spew attack, then jump in and start hammering him right afterwards, when he's vulnerable.
More goons will appear, but you can simply evade them if you like. Likewise, keep to your webs when tentacles start to sprout from the floor. When you reduce Dino-Carnom's health to minimum, you'll get a little quick time event where you need to try and pull out his tongue (at least you're wearing gloves).
Follow the onscreen prompts to essay this challenge, and complete the mission.