Just responding to some of your comments - bonuses to the roll are showing up as reducing the target number. So if you're seeing you need 5 and your bonus is +5, the original TN was 10. It's a bit confusing at first, but it's mostly just shorthanding to 'this is what you need to roll on the die after modifiers.'
And depending on what you're attacking and what you're attacking with, some creatures do have damage resistance - the imps in particular are resistant to non-magical damage.
