This, the companion volume to the Marine Training Manual, provides a game master guide to complete the core rules for I Love the Corps. It provides guidance on putting your own spin on the setting (and deciding just why Earth was abandoned in 2200), advice on creating adventures and campaigns based on the squad your players have come up with, premade colonies and monsters/aliens, and rules for designing your own. Plenty to get your teeth into here.
The Introduction lays out the contents in more detail, beginning by talking about the effect the abandonment of Earth has had on the universe as a whole... a bit of a rant and definitely from the point of view of the Colonial Dominion and the more rabid members of the Colonial Marine Corps - you know the sort, maybe an eager young recruit who has swallowed everything he's been told uncritically and with no life experience to balance it, or the veteran pontificating over a beer in a veteran's club to an audience of like-minded souls. It then explains the purpose of the book and how it is made up of three sections covering various aspects of game mastering this game. And there's the obligatory 'Players Keep Out' notice, as if nobody ever both played AND GMed a game they enjoy!
First up is Section 1: Special Operations. This begins by pointing out that the first step in designing an adventure or a campaign is to determine a collective purpose for the party. If your players already have characters, what sort of things are they good at? Or you may decide that you want to run covert ops, deep beind enemy lines (or whatever) and so inform your players so that they can come up with suitable characters. It then runs through various suggestions for squad types and what sort of missions to send them on to get you thinking about the options. Ideas are far-ranging and even include non-Marine options - the residents of a space station, a gang of criminals or a group of mercenaries. Police/security or rebels are also options. As I read through, another one comes to mind: the media.
Whilst all these options suggest appropriate campaign themes, the discussion moves on to look at wider themes like conspiracy, corruption or attempts to answer questions such as Is humanity worth saving? Are aliens manipulating us? Are psychics a threat? Or perhaps this squad are soldiers not of the Colonial Dominion but of another national power. Propaganda. Experiements gone wrong. Pirates... or even a dark comedy. High action or gritty reality. Out-and-out horror survival. There are so many choices, so choose wisely. This moves on to discuss creating the right atmosphere by the way in which both Action Scenes and Narrative Scenes are played out. Maybe you want to induce paranoia or force the squad to make difficult decisions.
Then we get down to the rules and how to use them to best effect in creating the story you'd like to tell with your group. This also covers deciding how lethal (to player-characters) you want your adventures to be, delivering mission briefings, even running the squad through at least part of Boot Camp before the adventures proper begin! Within a campaign, will the squad travel the galaxy, or are they stuck on an unpromising lump of rock and have to defend it or merely survive?
Next, Section 2: Intelligence Report explores how the game is designed so that each GM can fine-tune the setting to suit the stories they want to tell. For a start, why did Humanity abandon Earth? That's up to you, but if you find that a scary proposition there is advice and guidance to help you decide on what happened in your universe. Even once that is decided, there is plenty more to figure out... like how much the average Colonial Dominion citizen knows about it. Dark secret, something uncomfortable that people just don't talk about, or just another historical fact? If they were driven off by an alien invasion, what happened to the aliens? Do they still pose a threat? As you can imagine thinking about these considerations raises a lot of questions which you are going to have to answer, preferably before your group starts asking them. Fortunately there are lots of ideas to pick through. Meteorites. Infections or mutations. Environmental destruction. A massive solar flare. If you choose one of the proffered options there are notes on how that will affect the rest of the setting.
The discussion moves on to how to describe the different environments in which the squad is likely to have to operate. Everything from orbital habitats to jungle villages are given a few paragraphs on which you can build. The next topic is the creation of entire colonies from scratch. There's a wealth of detail here to help you come up with varied, interesting and vivid colonies for your Marines to visit. This is basically world-building, you'll need to decide everything from what the planet is like to the people who live there and what they do and what the indigenous wildlife is like. Sample colonies and story ideas are provided to get you started. Finally, there's a lot about equipment, especially vehicles for air, sea, land, and space travel.
The final part, Section 3: Threat Assessment is all about creating opposition for your Marines (and allies as well, of course - not everyone they meet wants to kill them!). There's a huge amount here of how to set them up according to your needs - human combatants to monsters and aliens that will freak out the most grounded and balanced Marine. It's all constructed around the core ruleset, so a vast number of Aspects are provided to make truly horrific adversaries that work according to the same game mechanics as the Marines facing them. The names may be a bit silly at times, but the flavour is there to build opposition that's scary, unstoppable or whatever you want to make them be. Psychic abilities are included, of course, and there are notes on novel forms of armour and weapons - and other tech - that you can use to make aliens really... alien.
Overall, this book enables you to take the core rules and shake and bake them into a kick-ass game of military adventure in a science-fiction universe, with layers of horror that may be applied as you see fit. The amount of customisation that you can do to make your game really your own is awesome!