I'm having second thoughts on using the Hive Thetus Crusade. The reason for this is that I think that the crusade and its markings were created as back-story for a specific player's army (and I don't know who that player is, so this isn't about *him*). If so, then all of the key members and the outcome/conduct of that crusade exist. What I don't want to do is arbitrarily contradict any of that, even if it resides at the level of fan fiction. I'm not totally against using the crusade, but I'm still entertaining options for creating a totally new one for the purposes of this project.
I've drawn up an initial map for the first mission. I'm in the process of creating the playtest tools (an index for the map so that players providing feedback can have a handy way of identifying specific points and providing alternate solutions in a way that everyone else can understand). Before we get into playtesting, though, we'll need to establish a common understanding of our intended outcomes so that we're all working towards the same goal (rather than having multiple different understandings that would result in working at cross-purposes, making our efforts more difficult).
The guiding principles presented in the main Indomitus Project post
remain relevant. However, some aspects of the Space Hulk game need to be discussed. What I present below is my own opinion and does not indicate a final decision for a way forward. Hopefully, feedback and reasoned discussion will shape conclusions from the broader perspective of multiple players; and we'll be able to use that broader perspective as our concepts for playtesting and finalizing the missions.
The most important thing to remember is that Space Hulk is a game in which one side is at a disadvantage. The Space Marines, encased as they are in the ultimate personal armour that the Imperium can provide, face horrifying odds. While some missions are easier than others, the general trend is that the Space Marines will suffer significant casualties. While luck is always a factor in games that use dice, if we assume an "average" for the luck factor (favoring neither the Space Marines nor the Genestealers), and if we also assume that the Genestealer player uses an "average" level of tactics, then the Space Marine player must employ good tactics in order to have a chance for victory. I've played games where victory for the Space Marines was by the slimmest of margins. I've also played games where simple bad luck took effective tactics and flushed them down the toilet of loss. The Genestealers have optimal tactics for each of the missions, but many players get by with some fairly basic tactics. Overall, the Genestealers are much easier to play and much more forgiving (though they can't just be used randomly).
So the relative power levels of our Indomitus missions will attempt to preserve that balance where the Space Marine player must rely on good tactics in order to have a hope of winning and where the slightest mistake might cost him the game.
As far as the maps go, there are several key factors.
First, how they are set up matters
. The length of a corridor, where doors/bulkheads and corners are placed, the proximity of intersections - these things are what drive the Space Marine player's tactics and enable/limit the effectiveness of the Terminators. As far as corridors go, the number and length of tiles of which they are composed is especially important when it comes to the area effect weapons (the heavy flamer in the base game, but other weapons in our expanded list). While a corridor that is five spaces in length doesn't have much impact on movement, there is a big difference between that corridor using a single five space tile and a corridor using a two space and a three space tile (ask anyone that has fired a heavy flamer in the latter setup). Similarly, placement of corners has a significant impact on movement (mostly for the Terminators) as well as line of sight. This drives how/when blips are revealed and impacts overwatch shooting. So a ten space corridor presents different tactical choices than a corridor that consists of two five space corridor tiles that are perpendicular to each other. Doors present the same sort of tactical challenge, though this can be mitigated if they are left open.
Second, where the Genestealers start and where the reinforcement blips enter play drive both the Genestealer and Space Marine tactics. These offer the Genestealer player choices in how to approach the Space Marines; and they force the Space Marine player to ensure that his choices allow him to respond to whatever choices the Genestealer player makes. This is compounded by the number of blips the Genestealer player starts with and brings onto the map each turn - the more the better.
Third, the mission objectives drive the strategies of each player. A mission in which the Space Marine player needs to get a specific model to a specific point means that his whole strategy will revolve around protecting that model in order to get it where it needs to be and can do what it needs to do (all other models can be sacrificed as long as model X does what he needs to do). A mission in which the Space Marine player must destroy a certain number of Genestealer models is an entirely different challenge, however, and the Space Marine player will likely try to set up strong overwatch positions. Meanwhile, a mission where the Space Marine player needs to get a certain number of models to point X requires him to adopt a maneuver strategy, getting his models where they need to go while being able to deal with whatever Genestealers he encounters. The Genestealer strategy will generally be the opposite. In the first example above, the Genestealer player will likely focus his efforts on killing that one model; in the second example he'll try to bypass the overwatch positions or will swamp one or two of them in order to get within the ranks of the Terminators; in the third example he might come from as many directions at once and slow the efforts of the Terminators while setting up lots of Genestealers in key locations. And the Genestealer player can just as easily use the simple strategy of attempting to kill every Terminator model on the board. Generally speaking, the Genestealer player only has to prevent the Space Marine player from achieving his objective in order to win the game.
Third is the number/composition of Space Marine models and where they start. Using the Sergeant with the power sword presents a different tactical challenge than using the Sergeant with a thunder hammer. Likewise, the assault cannon and heavy flamer bring an increase in firepower, but the drawbacks of limited ammunition. While our missions will be playtested to the models provided in the basic 3rd edition set of Space Hulk, we must also keep in mind our expanded weapons rules and how these might change the tactics of the Space Marine player. For example, a mission where the heavy flamer model must do something becomes slightly easier if the combi-flamer can do the same thing (and the Space Marine player has a model with a combi-flamer). In missions where one of the heroes (Captain, Chaplain, Librarian) may be used, the special abilities of these heroes will have a significant impact on how the Terminators are used (and may even be central to the Terminator strategy). One of the key decisions that the Space Marine player will have to make is the starting positions of the Terminators.
Ultimately, achieving the "proper" game balance (difficult for the Space Marine players to achieve their objectives, but achievable) will be at the level of art. While there might be some scientific aspects, the aggregation of all of the elements cannot be done on the basis of a formula.
Additional ideas about Space Hulk can be seen at the Board Game Geek
(BGG) pages for the game, especially the strategy forums (if you're not familiar with that site, scroll down to the forums header and then select the Strategy tab). I'll probably review the BGG discussions later and then attempt to present some key ideas here.
Feel free to comment on this so that we can adjust accordingly as we move forward into playtesting and finalizing the missions. Once we finalize our playtest guidelines, I'll present the first mission. We'll conduct each mission's playtesting/finalization in turn, focusing on one mission at a time.