Useability Guidelines For Computer Games

Use a splash screen for an emotional opening sequence, but limit the number of displays before the actual game to the minimum.
Implement the game's main menu with custom graphics.
The left softkey should be used for Select or the Options menu, the right softkey for Exit/Cancel/Back.

Design the game so that it does not require the user to press two keys simultaneously, as this may be difficult.
Use the navigation key as a primary game control. Users should be allowed to move with the navigation key and select items/perform actions with it.
Use only one key for one command.
Inside the game, the left softkey should pause the game and bring up the main menu or a pause menu. The right softkey is optional; it may be disabled completely. If enabled, it should be used for exiting the game (with confirmation).

The game should go into Pause mode for both players if one of the players is interrupted. It must be possible to continue the game.
The player who was not interrupted should receive information about why the game is being paused. For example, "Waiting for the other player to continue."

Design games so that the interruption of one player does not interfere with the other players' game. The interrupted player's game can be switched to the background without pausing the game or the player can be dropped from the game. The preferred action depends on the game type.

Provide appropriate status information depending on game type (for example, character health, ammunition, score) clearly. Make sure the amount of status information is not excessive; one or two status indicators are plenty for most games.
Provide clear feedback on essential elements in the game: when a level is completed, when a bonus level is reached, when the players achieve something (score a goal or kill an enemy).
Essential elements need visual feedback so that the game is playable without sounds.
In multiplayer games, provide clear feedback about who has won and lost. Communicate to the user about their performance by using "you" instead of a name or color symbol.
In multiplayer games, after the user has sent a challenge to a friend, provide feedback that the challenge has been sent successfully

Make the game a minute to learn, and a lifetime to master.
Provide rewards early on to keep beginners motivated. Rewards can be new levels, abilities and weapons, for example. Providing rewards in a random schedule maintains motivation for the longest time.
Provide different difficulty settings, if feasible.
Do not make the game more difficult by altering constants, such as the physics model attributes. Instead the challenge should come from difficult tasks.
Make the game as engaging as possible: challenging, unpredictable, but not unbeatable.
When feasible in multiplayer games, provide player ranking and player matching systems that try to match players of equivalent skill against one another.

Keep the default sound volume reasonable; not too quiet, but not too loud, either.
Allow the user to adjust the sound level of both background music and tones.
Sounds must not be too loud or too high-pitched, and users must be able to turn sounds off easily.
Background music should be synchronized for all players to avoid an auditory mess.

The appearance of game objects and characters must be easily inderstood.
Different items must appear clearly different and their functionalities should be distinctive as well.
In multiplayer games, characters need to look different enough so that the players can identify who is who.
In multiplayer games, make sure that the colors of the characters appear the same for all players.

Provide in-game help to the user. Training mode is the preferred solution.
Add information items, such as tips and hints that are revealed in certain locations or events, to the game.
Allow the player a chance to pause and check game controls easily during a game.
The in-game help feature should not stop the game. The player should be able to skip the help if they choose.

There should be a high score list, if it fits the game idea. A high score list motivates the player to compete against their previous score or some friend's score.
Provide preset results and make getting to the high score list feel like a reward.
Do not force a player to enter a name. If they does, use the last name as a default in the future.
Games become more interesting when players can compare their performance with the performance of possible community members. Give the user the possibility of updating their scores to the high score list of the game community.
Show in the community high score list both the scores of some of the best players and the scores of players who performed closest to the user.

Provide an easy way to restart single-player game. For example, in the Game Over screen, provide a "Replay", "Play again", or "Restart" command, taking the user back to the beginning of the game, with the same settings as before.
In multiplayer games, provide a quick way to start a new game with the same opponents.