| The following is an on-going list of very, very strongly recommended guidelines for anyone developing a videogame. These should be obvious, but as my exasperating experiences with Black & White illustrate, they are not always followed.
No unskippable cinematic sequences. If you want to ensure that the player watches the whole of your lovingly-crafted non-interactive plot chunk, either a) autosave beforehand, or b) allow them to review previously reached cinematics.
No tutorials. The absolute maximum that should be done to introduce new players is to make the first mission/area slightly easier and feature a good proportion of the game's features. Time spent making a tutorial is better spent making the interface more intuitive. Alternatives to tutorials include online help systems (see Dungeon Keeper, Card Fighters Clash).
Minimise interuptions. Disk accessing pauses should be as short as possible. Chopping the game into discrete levels is not completely necessary in the post Half-Life world, but may still be done.
Support more than one user. (To allow more than one person to play a single-player game and utilise seperate banks of save games / a seperate quicksave).
Balance realism with playability. Sure, if you're writing a military sim the player will be prepared for extremely harsh realism, but in most cases there should be a compromise.
Don't add features that don't make the game more fun. See Black & White for more information.
If the game has to be released incomplete, at least make it completeable. See Black & White for more information.
Don't make a game that can't be done with current technology without object-defeating sacrifices. A good rule for the hundreds of doomed MMORPG developers out there.
Balance every challenge with a suitable reward. See a certain game beginning with 'B'...
Do not enter into a publishing deal with Electronic Arts. See Richard Garriott for more information.
More to come.
Yes, possibly the title of this node is bad. Also, the usual GTKY warnings apply. | 
