EPTAnyways, I'm actually pretty fond of this setup because even though it's a completely open game, players who encounter the setup for the first time are tested as to how much they understand the fundamentals of mafia. The version I hosted here for TL actually is streamlined quite a bit to make play less complex and certain things more obvious, but the core concept is the same.
First, it should be obvious that the Angels are the only scum team able to kill at night, and cannot be eliminated except by lynching. In fact, from this point of view, the Angels are the only true mafia team in this game. Both Town and Demons have to eliminate the Angels to fulfill their win conditions, and should work together to do so. From this point of view, we have a 15/3 game, with 1.20 kp for the mafia, and a good slate of power roles for the town. What are the demons from the Angel point of view? "Town" power roles! From the Angels' perspective, in some ways it doesn't matter whether demons or townies are eliminated, once their combined numbers are cut down to the same or fewer number as the Angel team themselves, they win. But there is the subtly where the Town and Demons have some infighting of their own, so it's up to the Angels to keep that going to their benefit. Overall, of course, a 15/3 game with 1.2 kp isn't exactly favorable for the Angels, especially when one considers the abilities available to their combined Town/Demon adversaries. In fact, one might say that the Angels' chance of winning are approximately one in three!
Of course, the other game in play at the same time is the struggle between Town and Demons. But before going further into this, the importance of votes needs to be established. In a typical mafia game, the win conditions can be reframed in terms of votes each side controls. The town starts with a lot more votes, while the mafia starts with just a few. The town wins when all mafia votes are eliminated, while the mafia win when they catch up to the number of votes the town has. And the status of the game can be gauged the same way. When the town carries out a successful lynch, they reduce the number of mafia votes by one, while every night kill, and every forced mislynch reduces the number of town votes by one. Each side comes closer to victory by depleting the other side's votes.
Examining the Town vs Demon "subgame", one can see that it plays out as a 12/3, but instead of night kills, every other night, the Demon team can simultaneously gain control of a vote while removing a vote from the town. So in this way, every two nights, the demons are able to gain two votes relative to the town, just like your typical 1 kp mafia faction from this perspective. While the Angels are still alive, for both the Town and Demons' benefit, the lynch would presumably be focused on Angels when possible, leaving them to tangle primarily at night, with the demon hunter, sage, and corruption in play. In a way, the Angel kills would be similar to kills from a serial killer from this perspective, perhaps trying to keep both factions "balanced" but not necessarily succeeding. If and when the Angels are eliminated, then the Town and Demon battle blossoms to the forefront. The 12/3 ratio and the particular set of power roles provided (where Angels are much more likely to kill Town than Demon) lead to something resembling a balanced game of mafia. But of course, the Angels have to be defeated before either of these teams can win, leading to an approximate one in three chance to win for both of these teams, as well.
The set of abilities available to the Angel team are primarily offensive in nature. A strong kill, a chancy/snipe-style kill, and a pretty cruddy observe ability that might give the acolyte a better target in the future. The team has nothing else, the angels play pretty much like a traditional scum team where they need to avoid being lynched, and kill. If the Angels lose either their angel of death or acolyte, their offensive power is significantly blunted, so those two players need to stay alive.
The set of abilities available to the Demon team however, are primarily defensive in nature. A strong jailer which can protect their own or shut down any identified players with abilities. An additional pseudo-doctor against Angels only which can also foil the sage. The conceal ability also can be used strategically to hide information about the game. And the corruption ability which allows them to creep towards victory...but acts as a double edged sword. One thing to note, though, is that the demon team is the only team guaranteed to know the alignment of every player that dies! Anyways, both the twister and courier provide important, overlapping protection, so losing either early is a major setback for the team.
The corruption ability does not show its full potential until a specific turning point. While it's true that before that turning point, the control of a vote can be used beneficially in some situations, often the use of the corrupted town players' vote can lead to the corrupted player being identified, which drastically reduces the benefit of such a player to the demon team. And all during this time, the demon team is creating a bunch of new town power roles, whose power varies depending on the situation! The corruption action can also fail and accidentally discover an angel or the sage for the demon team, but if the demon team is on the ball, they should be able to identify with great confidence a target that is town and unlikely to be jailed.
What is the turning point, then? Well, it should be pretty obvious. It's when the demon team controls enough votes to control the lynch. But this is the turning point even if the angels, or various town power roles are still alive. Once the demon team reaches this turning point, the only way for anyone else to stop them from winning is to either successfully eliminate two or more demon votes during the same night with kills, or successfully cleanse a corrupted town player. And during this time the demons will be using their twister AND courier (if they remain) to foil such attempts against them. The corruption ability is a shadowy noose that is hardly noticed until it's established around the neck, and at that point it's very hard to get off.
The set of abilities available to the town are few, but important. The channeler is an obvious jailer, but making the jailed player public information further benefits the town. (Publicizing the courier's jailing also benefits the town, too.) There's a weak angel cop (in that it can confirm scum but cannot confirm town), and a weak demon cop combined with a very important pseudo-resurrector which regains town votes! And finally a weakened vigilante. The demon hunter can indeed indirectly identify angels with a failed attack, but a regular vigilante would have just killed the targeted scum anyways. But this role is especially important when the angels are still alive, as hopefully the lynch would be focused on eliminating angels, leaving the battle against demons up to this role at night. Losing any of these roles is a big blow to the town.
The sensing town players created as a side effect of corruption can vary in strength. When the town power roles are alive and still hidden, the sensing players are weak. But if the town power roles have been thinned out, these players gain in strength and become much more important. It's a balancing act for the town and these players whether or not to eliminate the demon vote or to make use of the sensing ability they have.
The effectiveness of many of the town's power roles also increase greatly when one scum team is eliminated, so it's against both scum teams' interests to do so prematurely! Weak investigators become strong ones as the inability to confirm town is removed, and even past results become more important. The moment either scum team is eliminated, the town's chances of winning increase greatly.
This game does include a lot of interacting elements, but having those elements known to all players at the start of the game allows players who think things through to try to extract as much benefit as possible out of them.
