I work for Modiphius on Dune: Adventures in the Imperium and Star Trek Adventures, so it’s no surprise I’m a fan of their 2D20 system. But its only recently with Dune that I’ve had to take a deep dive into the rules and noticed that 2D20 does a lot of things that make it more than worthy of an article.
In 2D20, you get a base dice pool of (unsurprisingly) 2D20 to roll to beat a target number. This target number is made up from two attributes that are usually different for each game line, depending on its needs. Dune uses Drives and Skills, for Star Trek it is Attributes and Disciplines, for Conan it is Attributes and Skills. It really depends on what the setting requires, but the rules behind them are the same. Any die that rolls equal to or less than the target number is a success, and the more successes the better. Roll a 1 and that’s a critical, netting you 2 successes for that die. Additionally, if your character has a focus (a specialist skill that applies) a roll of less than one of the two attributes that makes up the target number will yield a critical too.
This means it’s possible to roll 0 to 4 successes on 2 dice, and the gamemaster sets a difficulty in successes to achieve the task. But the difficulty can range up to 5. This is where Momentum comes in, which is one of the other parts about 2D20 I really like.
Momentum is gained by rolling more successes than you need. So, if the difficulty is 2 and you roll 4 successes, that’s 2 Momentum points to the group pool. Momentum can only go up to 6, so good rolls don’t make things silly. Momentum essentially represents what it is named after, the momentum your characters gain as successes build up in their actions, each leading to a better foundation for the next task.
Momentum is a quick and simple way to reward good dice rolls, and as it’s capped it encourages you to spend it. In most systems you are encouraged to hoard bonus points for when you really need them. But Momentum works best when you spend it freely and frequently. In fact, the system assumes some Momentum is being used on pretty much any roll, and spending it to overcompensate is a good way to regenerate the pool.
All this is leading up to my favourite thing, the difficulty 0 roll.
In plenty of games the PCs might arrive at a party and say “I’ll go around the room and see what rumours I can pick up” or something similar. Unless the GM has something specific in mind, you often end up shrugging or maybe granting a bonus later, or just making something up. But with 2D20 you can offer a difficulty 0 test and allow the PC to gain Momentum they can use in the scene later. It directly represents the advantage they have gained from asking around and checking out the surroundings. It might be spent later with the player referencing something their character heard or noticed in their initial investigation. “I’m buying an extra dice as I heard some gossip about this guy I’ll use when I challenge him.”
As much as a party this might apply to scouting a battlefield, planning a scientific endeavour or prepping your equipment before a dangerous hike. All things that done well might yield a bonus depending how well they were done, and in 2D20 it is baked into the rules and ready to go. In fact, it need not be difficulty 0 either. The GM can offer a roll with no real failure option to see how well they do. “This would normally be difficulty 0, but as you are outsiders at the party, I’m making it difficulty 2.” You might not get as much Momentum, but you can still ask around. By the same token the battlefield might be dark, the equipment substandard or the science something you are not familiar with.
So, whichever version of 2D20 you try, I recommend it’s worth a look. There are plenty of other good things about it, but its simplicity, momentum and difficulty 0 tests are my favourite aspects of the design. It has worked well for a wide variety of games and adapted to fit each one seamlessly, be it for Barbarians, Federation Captains or Sandworms.
The 2D20 Concept
If you are not familiar with it already, this is the system used for pretty much all of Modiphius’ games, such as Conan, Star Trek, Infinity, Dune and many more. But I should add that it’s not used in the same way house systems were many years ago, with games crowbared into them regardless of whether they fitted or not. This is one of the first strengths of 2D20, it is exceptionally adaptable and each time it has been used it’s been tweaked and adjusted to fit the game setting, rather than the other way around. Cortex Plus (Smallville, Leverage, etc) is another system like this, making both more of a concept than a rules system at heart.In 2D20, you get a base dice pool of (unsurprisingly) 2D20 to roll to beat a target number. This target number is made up from two attributes that are usually different for each game line, depending on its needs. Dune uses Drives and Skills, for Star Trek it is Attributes and Disciplines, for Conan it is Attributes and Skills. It really depends on what the setting requires, but the rules behind them are the same. Any die that rolls equal to or less than the target number is a success, and the more successes the better. Roll a 1 and that’s a critical, netting you 2 successes for that die. Additionally, if your character has a focus (a specialist skill that applies) a roll of less than one of the two attributes that makes up the target number will yield a critical too.
This means it’s possible to roll 0 to 4 successes on 2 dice, and the gamemaster sets a difficulty in successes to achieve the task. But the difficulty can range up to 5. This is where Momentum comes in, which is one of the other parts about 2D20 I really like.
Gaining Momentum
If you spend a Momentum point on the test you can buy more D20s for your pool. The cost escalates the more you buy, and you can only ever have a maximum of 5 dice in your pool. While 2D20 isn’t the only game to offer ‘beanie points’ Momentum does have a few differences to what you are used to.Momentum is gained by rolling more successes than you need. So, if the difficulty is 2 and you roll 4 successes, that’s 2 Momentum points to the group pool. Momentum can only go up to 6, so good rolls don’t make things silly. Momentum essentially represents what it is named after, the momentum your characters gain as successes build up in their actions, each leading to a better foundation for the next task.
Momentum is a quick and simple way to reward good dice rolls, and as it’s capped it encourages you to spend it. In most systems you are encouraged to hoard bonus points for when you really need them. But Momentum works best when you spend it freely and frequently. In fact, the system assumes some Momentum is being used on pretty much any roll, and spending it to overcompensate is a good way to regenerate the pool.
All this is leading up to my favourite thing, the difficulty 0 roll.
The Difficulty 0 Roll
In 2D20 you can make a test with a difficulty of 0, that requires no successes to succeed. As this means an automatic success, you may be wondering why you bother rolling. In this case it is to see how much, if any, Momentum you can gain. But difficulty 0 tests are not just something for players to try and get free points with. They are a neat way to represent scouting out an area or asking around to gain information.In plenty of games the PCs might arrive at a party and say “I’ll go around the room and see what rumours I can pick up” or something similar. Unless the GM has something specific in mind, you often end up shrugging or maybe granting a bonus later, or just making something up. But with 2D20 you can offer a difficulty 0 test and allow the PC to gain Momentum they can use in the scene later. It directly represents the advantage they have gained from asking around and checking out the surroundings. It might be spent later with the player referencing something their character heard or noticed in their initial investigation. “I’m buying an extra dice as I heard some gossip about this guy I’ll use when I challenge him.”
As much as a party this might apply to scouting a battlefield, planning a scientific endeavour or prepping your equipment before a dangerous hike. All things that done well might yield a bonus depending how well they were done, and in 2D20 it is baked into the rules and ready to go. In fact, it need not be difficulty 0 either. The GM can offer a roll with no real failure option to see how well they do. “This would normally be difficulty 0, but as you are outsiders at the party, I’m making it difficulty 2.” You might not get as much Momentum, but you can still ask around. By the same token the battlefield might be dark, the equipment substandard or the science something you are not familiar with.
Architects & Agents
I should also add a special note for one thing we did with Dune, and that is architect and agent play. As Dune uses a Drive and Skill and not an attribute, the physical aspect of your character is not applied to the test. As such, using the same system, your character can fight a conflict from a distance using proxies (like a group of soldiers) rather than wade into the fight themselves. While it keeps them a lot safer, and perhaps protects their identity, if the plan goes wrong, it’s harder to improvise a response as you aren’t physically in the scene. What makes this a great piece of game design is that not only is it possible in the 2D20 system, but it also doesn’t require any rules changes. You use the same rules system no matter what approach you take, the only difference being how the scene plays out and what you options are afterwards.So, whichever version of 2D20 you try, I recommend it’s worth a look. There are plenty of other good things about it, but its simplicity, momentum and difficulty 0 tests are my favourite aspects of the design. It has worked well for a wide variety of games and adapted to fit each one seamlessly, be it for Barbarians, Federation Captains or Sandworms.
He loved it! It made for a sudden change of game play...the PC's suddenly were now wondering what to do....why was she here? How did she get here? 
