Some Thoughts on the Rules Changes of Call of Cthulhu 7th Edition
I've had the opportunity to clock in a decent amount of time playing the Call of Cthulhu 7th edition RPG since its initial release in 2014. Like the previous editions, characters from one edition are very much compatible with previous editions, though the rules themselves have undergone a lot of tweaking and fine-tuning.
So what changed?
Looking at the character sheet the first thing you notice is characteristic scores no longer are in the 3 to 18 range but rather in a percentile range. You generate characteristics in the same way - 3d6 or 2d6+6, depending on the stat, but you multiply by 5. This makes it perhaps a bit easier to make percentile rolls against abilities but it doesn't affect gameplay very much. Looking at the quickstart rules for Chaosium's upcoming RuneQuest revision it doesn't seem like this change will carry over there.
Perhaps the biggest change is the addition of a full difficulty system. In previous versions of Call of Cthulhu, there was no difficulty expressed with a skill check. Now there are two ways to adjust the difficulty. Interestingly neither is a straight add or subtract from the chance of success.
First, for more static tests, there is now the concept of hard and extreme rolls. A hard roll requires rolling at half or below of the ability or skill rating. Extreme requires rolling under a fifth of the stat. In my experience this tends to make success very unlikely unless multiple characters are making an attempt at something. There is also the concept of bonus and penalty dice, often used for contested skill rolls. In both cases you roll additional "tens" digits of your percentile roll. If you have two bonus dice that means you'd roll 3 tens digits and one ones digit. You keep the lowest of the tens digits, greatly improving the chance of success. Penalty dice do the opposite, requiring you to keep the highest of the tens digits. When making a contested roll the character with the greater level of success (i.e. extreme > hard > standard > failure) wins. In the case of both having the same level of success, the one with a higher stat usually wins (though there are exceptions in combat). As a result of this, the resistance table is gone. I was a little miffed to see the resistance table gone but I find it plays very well at the table, making for fast resolution. Looking at the RuneQuest quickstart it looks like the resistance table is back.
Combat has been tightened a lot from previous editions. The game finally explains just how to use dodge. I rather like the way its done. First, when getting shot at all dodge does is let you dive for cover. In hand to hand combat you have a choice between dodging and counterattacking. When you dodge if you get a higher or equal level of success, you are not hit. When you counterattack, if you get a greater level of success your opponent misses and you land a free hit in. But on a tie your opponent hits you. This plays very well, giving the players choices to make rather than the constant "I dodge". Gunfire remains very deadly. If any attack takes out more than half your maximum hit points you suffer a "major wound". If you are brought to zero hit points and you have a major wound, you are dead, otherwise you are unconscious. This actually makes characters a tiny bit tougher than in previous editions as previously zero was dead and one or two was, if I recall correctly, unconscious.
A classic problem in previous editions was what to do if a needed skill check fails. In the 7th edition, players have a bit more control. They can optionally have luck points, allowing for the adjustment of dice rolls - though luck does not go back up very quickly. And characters can "push" a failed roll, allowing for a recheck with an identified negative consequence if that fails too.
Overall, the biggest thing to note is this is still largely the same game. Characters are fragile, though the optional rules in Pulp Cthulhu toughen them quite a bit for those wanting such a game. I've had no trouble at all using earlier edition adventures and stats with the new edition - I'm not talking about requiring minimal prep work - I'm able to convert on the fly. The game is still easy to teach to new players - I've had opportunity to do so. The character sheet is a bit more cluttered with its half and fifth for skills, but it is useful to have the information on hand.
I am curious as to what direction Chaosium will go in for future BRP games. The new RuneQuest seems to be avoiding going in the same direction, keeping the resistance table, the traditional characteristic ranges. However, some aspects of the difficulty systems seem to be present - for example longer ranges for missile weapons have half and a quarter chance of hitting. Similarly the game has special and critical successes and a defender needs to at least match the attacker's level of success when dodging. Of course I'm not certain Chaosium will be publishing more BRP games than RuneQuest and Call of Cthulhu and the games are still very similar to one another, albeit with different focuses.