We'll be using a percentile contested roll system. Of course, that means that we're rolling a d100 and the degree of success will be determined by how well you roll. The base difficulty is always 50%. Proficiency in the skill will increase your chances of success, which allows you to get above 100%. A roll of five or below is always a failure, and two or below has catastrophic repercussions. If you have proficiency that would bring you above 10%, then you can no longer have a catastrophic failure, but a roll of five or below still fails. A roll above 100% grants some unintended benefit, like, the attack is faster and therefore harder to defend against, or it does a bit more damage, or it uses less fatigue/mana than you intended. (
Let's say you're doing a stealth check and you roll 100%, the result would be something like, "you make no extraneous sounds only someone who is actively listening for a noise and it's also lucky would have the chance to hear you." If you roll an 80% the result might be You're very quiet, most people can't hear you, then you would not disturb someone who is concentrating on another task. If you get it closer to 60% the results may be you make some noise and anyone paying attention to hear you. You might even draw the attention of someone otherwise occupied. And of course, if you were with something like 40% there is what would be you making noise, Russell leaves break a branch everyone nearby hears you what people further away may not notice. Then at 20%, we've got, "as you try to be quiet and make some mistakes and stumble making a decent amount of noise." At 5%, "you drop something, and before even realizing you say oh s*** under your breath maybe a tad louder than even you intended." And it 2%, "you fall and make a lot of noise everyone around can hear." On a 110% success, then someone might need a critical success to hear, or by supernatural means, on their attention and listening skill to be able to hear you.