I’m finishing up the Magic chapter and starting on Conflict. A few things stand out that illustrate how a GM can make the game his own. One, spells are pretty easy to design. The level of the spell tells you how many targets you can hit, what damage die the spell should use, or most importantly, to what spells your should be comparing your new one.
Two, I just wrote up a pulse grenade launcher. It has some interesting details, but I really like the gear-level system. The launcher is level 4, which means that a 1st level character using it becomes pretty powerful (while there are rounds in the magazine). An 8th level character, on the other hand, is not going to be significantly more powerful with it. The GM can use the levels of gear to boost or maintain PC power as he sees fit.
Three, Rule Zero can really help GMs draw outside the lines in combat. The gameplay sample at the beginning of the Conflict chapter illustrates how the GM can design an action on the go, add difficulty if necessary, and even grant bonus damage when it makes sense. Of course, players can let GMs know if they were too liberal with the use of Rule Zero during each after-session review!