...which is most likely the other half. Combine the two and widen the definition of "God" to include "BOFH" and you get a near 100% of believers on the 'net.
They are not compatible but comparable. Religious people tend to believe in a certain creator and creation while considering other creation stories/myths to be either false or incomplete - i.e. they consider other religions to be incompatible with their own. Those who honestly believe we are living in a simulation - which probably won't be that many people in total as the 'simulation myth' is as of yet mostly a philosophical construct - can mostly be categorised together with deists in that they consider observations and rational reasoning to be sufficient to conclude the existence of a creator who designed and/or started the simulation [1]. This only goes for those who truly believe the hypothesis of the universe - or at least our part/view of it - being a simulation, not for those who just take up the subject to spin a yarn or impress others with their supposed erudition.
[1] this is a deep rabbit hole to go down into: did the creator actually design the simulation or did he only start it to while away some time on his gaming system? Is this a first-level simulation or is it a simulation inside another simulation, either as part of some sort of experiment or just as a mini game inside the game just started by some pimpled green-skinned lizard-boy on his Game-o-Saurus?