OK, first a disclaimer - I don't read comic books - haven't since Batman, Superman and Wonder woman were the only superheroes in print. Ironically, I am now pretty much up to speed on the Marvel Universe only thru the proliferation of movies over the last 16 years or so. Superman movies have been around since the late '70s but DC seemed limited to him and Batman until recently spreading out to the DCEU.
So, going into Suicide Squad, I knew nothing of the setup or characters. Tho, you will be pleased to know that Batman plays a small part in this movie by putting some of these misfits in prison.
The time of this movie is after Batman v. Superman with Superman's supposed death. With all the havoc of that battle of super heroes & monsters Amanda Waller (Viola Davis) presents a plan to high ranking government/military ppl that we need a squad of metahumans to counter any future attacks. They would be working outside of the government and as she said, "if things go wrong we throw them under the bus." This is a fairly dark comic movie.
Most of these metahumans with specialized skills are in Belle Reve Penitentiary, a dreadful medieval prison in Louisiana (a bit of reality in this fictional movie). Waller has one that is not in prison, Enchantress (Cara Delevingne) who has the ability to vaporize and come back with enemy military secrets from the other side of the planet, so the brass is convinced to go with the plan.
Waller has Col. Rick Flag (Joel Kinnaman) take control of the metahumans by implanting them with explosives so they follow orders or die. The Suicide Squad taken out of prison consists of Deadshot (Will Smith) a hitman who never misses a shot, Captain Boomerang (Jai Courtney) who is Aussie and has a deadly boomerang (duh), El Diablo (Jay Hernandez) a living flame thrower, Killer Croc (Adewale Akinnuoye-Agbaje) a tuf, scaly mutant and as Harley Quinn (Margot Robbie) a psycho former psychiatrist who is in love with Joker (Jared Leto) who is not in prison and is not a part of Suicide Squad.
That is the reluctant Suicide Squad and they have to go after some very powerful supervillain trying to take over the world using their combined skills. I could not find many production pix of the right size for linking and of the few I did find seemed to always have Harley Quinn in them. Could be that she is the fan boy favorite, a gorgeous, fun, flirtatious cutie who is deadly psychotic.
Col Flag, Harley Quinn & Deadshot
Harley Quinn & Deadshot
This movie was not well received by the critics. The aggregate reviewers on Rotten Tomatoes gave it a 26% fresh and their consensus was, "Suicide Squad boasts a talented cast and a little more humor than previous DCEU efforts, but they aren't enough to save the disappointing end result from a muddled plot, thinly written characters, and choppy directing." However, 74% of audiences liked the movie, so this is one of those movies not made for critics but perhaps for fans, like the 17.6K hardcore fans who signed a petition to shut down Rotten Tomatoes because they always give The DC Extended Universe movies unjust Bad Reviews. The guy who started that petition admitted that after thinking he knew it was pointless and only meant it for DC fans to vent their anger.
I can see the problems with the movie. Started out OK as we are getting a backstory on all the characters and how they came to be, such as the unhealthy pathological romance between Dr. Harleen Quinzel (Harley Quinn) and her psycho patient Joker. (Many of those who panned the movie, mentioned the excellent portrayal of Harley Quinn.)
The movie did drag a bit in the middle but overall it worked for me. Having read some of the reviews, it seems like they are humorless overthinkers who cannot suspend disbelief and enjoy the absurdity of a comic book movie that strays a bit from the neatly wrapped stories they are used to.