Dice mechanics

Roll 1d20 to resolve conflicts.

• 1 - critical failure
• 2-5 - failure
• 6-10 - success at a cost
• 11-19 - success
• 20 - critical success

This is one of the simplest systems. You do not need to do table math or have more than a D20 to perform any oracle consultation. (It also, I think, will disappoint players who are hoping to see a character grow in power. Since there are no modifiers they are not able to do that in the usual way.)

Character builds

Class-based, and selecting moves from within the class. You do not get better at any particular rolls--moves just allow you to perform rolls in particular circumstances that other characters cannot. Those moves may have their own resolution ladders for the outcome.

The closest to being "good" at an activity over another character is a reroll. You may qualify for a die reroll that allows you to re-attempt a failure and keep the second result.

This is close to but counter to Spire where you qualify for additional dice and roll in a pool. Quest does not roll a pool and keep the best--it simply allows you to re-roll by expending some kind of resource.

Reaction

Probably a good introductory system. The rules are largely written on ability cards that characters take; this means your character sheet is largely your rulebook and you can build that up as your character advances. Since there is no table math and only a single die is needed you can also play it with little more than a couple of phones and the desire to do so.

I don't think I would build a MUD around this rule set. It is easy to learn but players will never experience "numbers going up," they would simply unlock more verbs.