Space Quest V: The Next Mutation

To my mind this is certainly the pinnacle of Space Quest and as pitch-perfect spoof of Star Trek as we'd get before Galaxy Quest. Like King's Quest VI this was where exploration was somewhat phased out and shorter, more story-driven sequences phased in, but there's a lot of highly memorable encounters and sequences in this game, with a stealthy finale of raiding the enemy mothership at the end that calls to mind the original Space Quest.