A basic description of the adventure taken from the booklet:
"This adventure is suitable for Human Tier 1 characters with the IMPERIUM Keyword. The adventure takes place entirely on a battlefield, making it most suitable for characters with a military calling. The Agents will be organised into a battlefield squad. While it would make sense for all the Agents to have the Imperial Guardsman Archetype, a personnel shortage has forced the Astra Militarum to sweep up all kinds of individuals and send them into battle as part of the Gilead Gravediggers’ Penal Brigade."
The adventure notes which archetypes are are prudent for the adventure given it's a penal brigade including a new Framework to use for the adventure.
If you haven't picked up Forsaken System players guide we do see a note of a Grapnel Launcher and a Demo Charge in terms of new equipment/weapons. Admittedly I don't directly recall if the demo charge was from Forsakenn System but I feel something similar to it is in there.
Also provided are Smoke Grenades and a Breaching Ladder, and a Frag Bomb.
Throughout the adventure are instances of obstacles common to a siege like scenario from scaling a wall to fortifying a position, to trying to lead a tank through a mindfield. All of these would be useful to take and put in your toolbox for any sort of adventure, not just a guard campaign.
Provided we see some new (and old) notes for the Bestiary:
- Commisar Shrake
- Penal Brigade Trooper
- Traitor Militia (including Sniper modification)
- Doomed Youth
- Traitor Guardsman
- Cravax the Claw
Most interestingly, and a mechanic I feel can be lifted most easily elsewhere, is the "Calling for Support" section of the adventure.
PCs can spend Glory to call in various effects from higher up in the chain of command. These effects can be Artillery Support to a Spotlight for difficult to see battlefield sections.
In turn the GM gets a similar mechanic called "Battlefield Ruin" which is a bit like Narrative Declarations for the GM to modify the battleffield with (new and useful for sure as any new way to spend the resources of the table is good)
In conclusion, for what the adventure says it is, 'Bloody Gates' is incredibly competent and offers mechanics that any guard game emulating Only War would find incredibly useful.