The DC animated movies had an interesting trajectory since the days of the animated universe, from pretty harmless (limited amount of blood and violence, no gore) but mature content to extremely violent and gory movies that seem to swing from smart and mature to childish and stupid at a whim. Assault on Arkham, which is less a Batman and more a Suicide Squad movie with Batman as an important guest character, is an interesting mix, with a lot of violence and death, but drawn with very limited amounts of blood and next to no gore.
What makes it odd, because sometimes when characters die, the blood and gore is a pretty good visual marker of how final an event is. Here, sometimes you’re not sure if someone died or just lost their head (like a lego or playmobile figure). Violence without blood and gore is still violence for violence sake and not better than the other DC animated movies who went full gore without needing to.
Content-wise it’s more on the mature side, with the Suicide Squad doing their usual thing and with the mission soon leaving the original mission parameters. I dislike how disposable all the characters actually were in the end and how little any of the villains cared about their team members, and while that just reinforced their bad nature, I found it a bit unrealistic, as humans are still humans and even among criminals not everyone is a full-blooded sociopath.