Well, the humor was certainly important. And the graphics too, they were nice.
But a really important thing was being able to type things into a *machine* and (for a 8-9 year old kid) this computer *understands* you. Albeit it especially understands all the cuss words you know.
Most important though, was that we did this as a *group* of 8 year olds, talking to each other about what we were going to type in next into the system. We went to my friend's house to play it. I would have tried to do it all myself, but my dad refused to buy me a computer till I was sixteen (six years later). He felt I needed to master the 'typewriter' first.
Would be awesome if the new SpaceQuest had online group gameplay (and I mean that literally, not sarcastically), because I'm 34 years old now, and it's harder to walk to someone 34 years old and say, "Hey, let's see what happens if we type into SpaceQuest next?"