This is actually something I’ve considered quite a bit; I think that perspective can make or break a game. For example, if there is a creepy noise:
I hear a sound - I'm starting to get a bit creeped out!
You hear a sound - you're starting to get a bit creeped out!
Jill hears a sound - she's starting to get a bit creeped out!
The first is the PC telling the player about something, and sounds a bit scared; the second, the game is ‘forcing’ something on the player (the feeling of being creeped out), which can get a bit annoying if done poorly; and the third is more a simple status - we may not care about Jill at all.
However, the vast majority of games stick with one of those three, usually the first and second, because usually, they are trying to be invisible. But what about other responses? Instead of treating the player as a puppet master, actually involve them in the game; make the characters know that they are being given directions, say, as if player is typing responses through something like text messaging:
Susie: Ok, I opened the door.
Susie: There's a weird man there!
You:x man
Susie: He's just standing there. Hold on, I'll tell him to leave. He's really creepy...
You:close door
You:close door
You:x man
You:look
MESSAGE SEND FAILED
Or, for even more creepiness… have the character refuse to respond:
>get lamp
Straining, Fred finally tears himself away from your control! He stares up at the corner of the room, as if he's looking right at you.
>get lamp
Fred doesn't belong to you any more, player.
Fred exits the room to the north.
>north
Who are you talking to? There is no one here to obey you any more.
>look
The room is empty, player. Go torment someone else.
You get even creepier than that, too; it’s not too hard to set up a section that looks like a command prompt, but that isn’t; when the player starts typing (say, “open door”), it instead types out “kill man”, or something equally as horrific. That’s a concept I’d really like to see - forcing the player into situations outside of just participation, taking them from “That character just killed someone!” to “I just killed someone!”
Obviously, it could go the other way, too; in a more comedic game, the player could get fed up with the player and solve a puzzle on their own, or start daydreaming after too many ‘wait’ commands and miss what the player says next - or even the parser itself could interfere:
[code]>get vase
Fred picks up the vase, spliling some dirt on the conter as he does so.
x vase
Wait, sorry, that was terrible. Let me try that again.
Fred actually spilled some dirt on the conter.
x vase
Oh man, I’m an idiot - it was a counter! Just be glad I didn’t misspell it without other letters!
north
Oh right! Sorry! Um, the vase is really pretty and - no? sorry, I’m a terrible parser, BAD PARSER, BAD PARSER!
Fred walks north in disgust AT ME! BECAUSE I’M A BAD PARSER!
etc.[/code]