It's a pretty good start to, what would be a by-the-numbers heist film, if not for the super-villains and asylum full of insane criminals. KGBeast gets killed off before the mission starts to set the stakes and Harlequin and Deadshot have sex, I think to set up a conflict later in the film that never really pays off. Actually the attraction between Killer Frost and King Shark is far more interesting and sadly goes nowhere. Is she genuinely interested, or just playing up to King Shark for protection in case things go south? Things start to get complicated when the team discover that the Riddler has uncovered a way to deactivate the bombs in their heads and used that to go AWOL from the last Task Force X. Nigma turns out to have actually planned this whole thing, including getting captured by Batman and thrown back into Arkham, just to get back at Waller. Not to harp on this, but that's a way better plot than Suicide Squad.
Having the voice actors from BTAS is pretty cool, but the look from the Arkham video games jars with this and is a little distracting, especially with Hulk-Bane in the big finale. I'll get to it more in the upcoming Suicide Squad Superhero Media, but this concept really shouldn't be too hard to get right and make a tonne of money out of; it's The Dirty Dozen with supervillains, pretty simple pitch. Although I like the twist with the Riddler's scheme, it's not actually all that necessary, a quick heist plot with a few protagonist deaths would work just as well. Hopefully we'll see this concept done right in live action at some point.