The black suit is one of the two suits Spider-Man gets and plays as the villain version of the decisions you make. This is much more powerful than the red suit, however it doesn’t really get good reviews with the civilians of Manhattan.
Status[]
If the logo in the lower left corner is the red suit, civilians will compliment you. If the logo is the black suit, civilians will run from you in fear. They will also steal big Mac's like the jerks they are!
Black Points[]
Performing an act of evil (such as throwing a car in the first two zones in the game (aka the first and second parts of the game), answering wrong on Wolverine’s questions, fighting him while there are Infected Citizens in his battle, and basically using the black suit in general gives you Black Points, and having enough of these will shift you into what I like to call Dark Mode, where the logo in the lower left corner is the black suit.
Decision Making[]
While the Hero choices are, well, heroic, Villain choices are really bad. For example, choosing dark when the two Thug leaders are about to kill each other will make you just let them pull the trigger.
If you go through most of the whole game in the black suit, you will end up throwing that sonic wave device thing off its tower and let the Symbiote’s live. You will then go on the S.H.I.E.L.D Helicarrier in the black suit, being able to get there thanks to Vulture. Choosing villain once more while reaching for Venom will make you just kill him. This brings up the Non-canon Bad Ending, where you rule Manhattan and the Symbiotes along with Black Cat as the Symbiote King and Queen respectively while Black Widow sends Wolverine (In Symbiote form) to kill you.