I was thinking there could also be a dice system added for the outcome of significant actions. Using a d20 sounds like the best idea all around. And you can add bonuses to it from your stats. 1-5 would result in horrible failure, with 1 being absolute failure. 6-10 could be minor failure, succeeding in some things, but failing overall. 11-15 would come out to be success, and then 16-20 would result in great success, with a twenty being absolute success.

For example, you would attack a group of twenty lemurians. You roll a 14 and add your ATK Stat of 2 to it resulting in a 16.

The Miner charged with a blast of heat and chunks of molten lava erupting out of his thrusters. He sliced and diced as the lemurians let out their reptilian screeches. Claws and jaws snapped at him, but his evasiveness and armor stood true, letting him know through the humanoids with relative ease.

See? Depending on the outcome of your roll and your stats, it could all go desperate ways.