In-game tutorial

COMPLETE TITLE:
[HL] In-game tutorial - simultaneous func_door_rotatings

This is more of an experiment than a real hard-needed example map, but since someone had trouble finding out how to do rotating doors with glass, I figured I could as well make an example map and put in an old idea of mine: in-game comments, sort of an in-game tutorial.

So, the example .rmf is somewhat cluttered with extra entities and all for the speech system (speech icons don't work when another speech is commencing, for example, so that costs a few entities, and of course there's the env_message entities needed :)).
I'm thinking about doing this some more, hiding the speech system entities in a seperate part of the map next time to make the example .rmf itself more clear.

So, what do you think about this idea? In-game tutorials?