At the beginning I experimented with halving all the weapons damage. Makes for a quite different feeling in combat
Had to modifiy the 'standard' files and didn't back them up before installing the next test version, so there's nothing left from that experiment.
'Real' modding ability (with mods selectable from the start screen) came late, and sadly I didn't have the time to do a "proper" mod I could hand out.
First thing I would try if I get to modding again is reducing weapon damage and expanding missile range and some firing arcs.