General Game Structure: Part 2

Here is a great tutorial on types if you haven't read it yet.
http://www.blitzbasic.com/Community/posts.php?topic=59233

I'd might do your example like this, keeping Update() within the type:

Graphics 800,600,0


Local intro:TRoom=New TRoom
Local CurrentRoom:TRoom = intro 'point CurrentRoom to the first room

intro.Name="Intro"

Local menu:TRoom=New TRoom
menu.Name="Menu"

intro.NextRoom = menu 'the room you enter when you press "Enter" key
menu.NextRoom = intro

While Not KeyHit(KEY_ESCAPE)
	Cls
	CurrentRoom = CurrentRoom.Update()

	Flip
Wend

Type TRoom
	Field Name:String
	Field NextRoom:TRoom
	
	Method Update:TRoom()
		DrawText Name,10,10
		
		If KeyHit(KEY_ENTER)
			Return NextRoom 'if enter is pressed, return the next room
		Else
			Return Self 'if not, then return the current room
		End If
	End Method
End Type