In Conan 2d20, the GM assigns a target number for any given task, with a baseline of 1 (meaning that 1 ‘success’ is needed to accomplish the task). This target number can increase based on circumstantial criteria, going as high as 5.
Each player gets 2 d20s to roll for each task resolution attempt. (with each individual d20 aiming for a specific number to be considered a ‘success’) The player may opt to purchase additional d20s to add to the roll to increase their chances of rolling ‘successes’ but in order to buy them, the player must generate ‘Doom’ (which is the GM’s metacurrency) or spend ‘Momentum’ from the party’s shared pool.
Momentum can also be spent in other ways apart from buy extra dice for task attempts. It can buy extra damage, armor penetration, situational modifiers, and many more fiddly bits.
Conan 2d20 is a pretty crunchy game. I love the flavor of it and have GM’d a campaign for my friends, but in my old age I’ve grown weary of games with too much rules-meat on the bone. I’ve been designing a game that utilizes the awesome potential of the Doom/Momentum currencies but with a simpler outlook and implementation. It’s pretty unique and awesome in my esteemed opinion! (I’ll share it with you guys some day)
@BlazingPoly - Conan 2d20 has a free download quickstart that explains their Doom/Momentum mechanic if you’re interested in reading without committing to a purchase.