We have all the logic in place already for shot/bot collision detection. If we gave shots mass, firing a shot would have a recoil. Being impacted by a shot would effect your velocity. Sims could be run where all bots have voluntary movement (.up, .dn, etc.) disabled and must motivate exclusivly via shot reaction forces (or some other means such as tie flinging or reproduction).
Shot mass could be fixed or proportional to the amount of its contents. Shots with more nrg would weigh more.
I'd also like to add a new very heavy shot type - call it 'shell' - which would be highly suited to motivation. Firing one would either deplete shell or convert nrg to mass at the same rate as .mkshell. Being impacted would add shell aka mass...
Comments welcome...