The plot is you are held in at a secret research lab and you are injected with a poison made from black widow poison mixed with tarantula blood, but instead of killing you it fuses with your blood. You become super strong, you can climb walls, you are super fast, and can possess any arachnid. Throughout the game you get more abilities and about half way through the game you battle a giant scorpion that is too strong to possess and you fall into a pit grey slime, an unfinished experiment to turn all humans into large arachnids. By some chance, this is the goo that turns people into giant spiders, but the prototype does nothing to a normal human After falling into the goo, you grow 4 more arms and you gain the ability to shoot webs from your mouth (Now a pincer-spider styled mouth.).
You gain a special ability to jump super high and you have an ability that makes you see in green, and everything that can hurt you turns black when you use it. End boss is a human inflicted with a mess-up goo that turns you into a giant black monster with long claws and a black tail. When you defeat him you just free-roam and you can use any special character you saw in-game (gaint scorpion, end boss, your beginning character, or you spider-like character, etc). What I have done is:
Wall-climbing code
SuperJump activator and superjump
SuperSpeed activator and super speed
Scorpion AI
WIP Scorpion tail sculpt (in Sculptris, around 30 thousand polys.)
ALL codes for first level (GUI activate/deactivate from button, scientist AI, sliding doors)
Thug AI

So, yeah. It's being done in Unity3D (NOT pro). It's my take on Spider-Man. I'm simply correcting all the mistakes done with the previous games, modifying the spider-man origin story HEAVILY, and sacrificing web-swinging and zipping for super-jump, super-speed and ultra-strength. It is done in a mixture of C# and JS. Scorpion tail so far has amazing graphics.

Sounds cool. Does it feel fun to play right now?

With such an elaborate story, if it feels good, it should do well!