I played a RTS not too long ago (Warhammer 40k? not sure). Anyways, it had some of the best tutorial levels I'd seen. First of all, the were well integrated into the story-line of the overall game. The had single, easy goals. The levels were laid out in such a way as your units were basically funneled to the goal and it had periodic reminders of what you should be doing if you got off track (in the form of a commander yelling at you).

I'm by no means an expert, but I did enjoy that experience and it was memorable.


My opinions:
-Don't make the tutorials feel like something that *should* be done before starting the game, make it part of the game.
-Make the levels easy and small (so you can finish it in a short time if you want).
-Allow some exploration, but design the level such that all paths lead to the same point.
-Reminders now and then what you should be doing: "Build the BARRACKS, MAGGOT!"

The difficult part is that tutorials depend strongly on game states. If the game is in a different state than expected by the tutorial script (due to the player doing something unexpected), the tutorial may break.

My impression is that commercial games solve this by putting a lot of effort into checks on the game state and into level design where the player has not too many options to go off at a tangent.

This is not feasible for low-budget / small games. I can see two options:

- Have a completely scripted tutorial, where the user triggers certain events, but cannot influence what happens. That is, the tutorial works similar to a slide show. Not very thrilling, but should work reasonably well - the main point of a tutorial, after all, is to get a visual/haptic idea of what to do to play the game.

- Leave all freedom to the player, but check for game state before continuing the tutorial. Whenever the game state is not as expected, either a) set it to whatever is required and issue a warning to the player ('you have slain the damsel in distress, not the dragon - allow me to correct this'); or b) ask the player to establish the required game state (this can be tricky, as the player may not know how to do it, or the game may not allow it)

One thing I like (which kinda fits in with the game-as-tutorial) is where the game gives you an explaination whenever you get/try something new. This is dead easy with something like Mario or Zelda - you get a little cut scene when you collect a new item. For RTSs and RPGs you can pop up a dialog box with something like "You've clicked the build button, heres how you build new structures...".

For the completely inept you can let them keep this help permenantly on, for a default you just show it the first time.

Rigid 'tutorial' where you can't do anything but follow the script (to the extent of disallowing any other commands except the correct one) are boring and don't help the player.