I'm having another dilemma with Derelict Delvers mechanics. I've got two ideas that are oppositional.
The first idea is a fairly simple and elegant mechanic that is tested through a number of games I am familiar with; using it and few tweaks would make a simple but powerful game that I'd love and enjoy. The catch is it doesn't wow me. The basic mechanic is 2d10+Stat+Skill with a build in success scale.
Roll less than or equal to 0: Critical failure
Above 0 but less than 5 is Failure.
6 to X is a partial success.
X+1 to Y is a Full success
and Y+1 to Z is a critical success.
The numbers can be juggled depending on the final Stat+Skill range of course.
The other idea is a lot more complex on its surface, but can be used to create a more dynamic system, the biggest problem is the removing of the "instant" results which is elegant enough to keep the focus on the characters actions, and the mental state of the player being "in the setting" rather than "in the mechanics"
The mechanic for this design is Stat+Skill+floating dice valued in a number of d6-es. Each die is searched for a value, and any dice meeting that value becomes a number of "merits" towards success. In order to keep the scaling of the previous mechanic one needs multiple dice to match the Difficulty assigned by the GM or the default rules. In this mechanic there are two roll types.
Task rolls which are your generic roll when you are checking for success.
The other roll is a Threat roll which comes up when the outcome involves danger and threat.
Threat rolls add another mechanic element, Threat. Threat has three elements. The Threat Rating (or Risk), the Threshold level, and the Trigger Event.
The threat rating is how dangerous something is in severity, and also its difficulty number for how many merits it must get for the hero to "pass" and not trigger the threat. Threshold is how many dice that fall out of the "pass/fail" test that fail the roll and build towards triggering the effect. If the game gets the "fail" dice of the Threshold before it gets the success merits, it activates the trigger event.
It is a bit rough at the moment and needs some balancing (so that failure is not exactly equal to success, thus making the roll simply 50/50 at all times.) The idea is to generate a reason for exploration and investigation: Hero dice are earned by doing the base Task rolls during non-threat instances and gaining information on some threats so it makes it easier to deal with them. Perhaps hero dice can only increase towards the "pass" side of things, and cannot themselves count towards the trigger event. In general I'm aiming for a mechanic that makes the threats tenser, and the tasks important (since the game is "dungeon-crawl" like, I want the entire process to be entertaining.