I loved this. Kobayashi, any suggestions for how to use the attack roll directly for damage?
Easiest thing would be to adapt the rules from Unknown Armies:
_add the two numbers from your roll together (if you roll 54, you inflict, 5+4= 9 points of damage). Count the "0"s as "10". Eventually add +5 for 2d10 weapons and +10 for 3d10 weapons. Or simply a +5 for big things that hurt :)
_for highly lethal weapons: the result of your roll is the damage (maybe a bit too violent but why not).