I wrote a design document for a small game I thought up recently so I have a plan before I start coding. As I don't have any significant experience in game design, I would much appreciate any feedback anyone who does have experience could give me. __________________________________________________

Title

The Valley of Fear

Genre

Turn-based adventure/strategy/puzzle

Setting

Fantasy

Platform

Windows XP

Target Audience

Casual gamers of all ages

Back Story

For unknown reasons, a dragon has abducted the princess, and he's asking for a very large ransom. In spite, the king has offered the ransom as a reward to whoever rescues the princess from the dragon. A brave warrior from the large valley in the east of the kingdom, known as the Valley of Fear due to its proximity to the dragon's lair, volunteers to embark on this quest.

Objective

Rescue the princess (probably slaying the dragon in the process).

Obstacles

• Terrain: The player character cannot move through walls, closed doors, rocks, trees, large bushes, or deep water.
• Monsters: Monsters will move to chase or intercept the player character and attempt to kill him.
• Darkness: Dark tiles limit the player's field of vision.
• Traps: Traps kill the player character under certain conditions when he gets too close.
• People: Some non-player characters possess items that the player needs, or block the player's path. They usually will not help the player unless certain conditions are met.
• The Dragon: The dragon controls many minions which

Solutions

• Doors: If a door is unlocked, it's a simple matter to open it. Otherwise, the player needs a key.
• Monsters: Each monster is vulnerable to at least one weapon and is blocked by at least one type of armor.
• Darkness: Some items affect the player's field of vision under certain conditions.
• Traps: Traps become visible when the player character is in one of a number of positions relative to the trap. Traps are not triggered if the player enters the tile from the correct direction(s) and most traps can be disarmed with a specific item.
• People: Talking to people normally turns up valuable information, including what conditions must be met before a non-player will give the player an item or allow passage through a particular location (if applicable).

Game Mechanics

Each character has two states of health:

1. Alive: The character may take actions as normal
2. Dead: All traces of the character are removed from the map. Their memory lives on....

Doors also have two states:

1. Locked: The door is only passable to characters with the door's key
2. Unlocked: The door is only passable to characters with hands.

Each turn, each character has the option to move any of the four cardinal directions, or to wait until next turn. The game waits indefinitely for the player to input a command before updating everything else in the map.
When a character attempts to move from one tile to another, s/he turns to face the destination tile. The effects of moving towards a tile with any of the following is as follows:

• Wall, boulder, a friendly character, tree, large bush, deep water: A sound specific to the objects involved in the collision plays. (An NPC also reacts to a collision with the player and other NPCs.)
• Door: If the door is unlocked, a sound specific to the door type plays and the player character enters the tile of the door. Otherwise, if the player has the door's key, the door unlocks, the appropriate sound plays, and the player character enters the tile of the door. Otherwise, a sound specific to the door plays and the player enters the tile of the door.
• An enemy: No movement occurs. If the active character has a weapon that kills the enemy, the enemy dies, and sounds specific to the weapon and victim play. Otherwise, a sound specific to the defender's armor plays.
• A trap: If the trap is entered from any direction that triggers the trap, the trap goes off, normally killing the victim, but sometimes moving him/her. If the trap is entered from any other direction, the trap does not go off, and is disarmed if the character has the specific item that disarms the trap.

Game Shell

• Title Screen: Displays the title of the game and copyright information, and a prompt to "Press space to continue" for up to 7 seconds before fading through black to the game screen. The player can move to the game screen earlier by pressing space.
• Game Screen: Displays the area of the game world visible to the player character. When the player wins, it fades through yellow to the victory screen, or when the player character is killed, it fades through dark blue to the game over screen. The player can also give up by pressing Escape, which will make this screen fade through red to the title screen.
• Game Over Screen: Displays "Game Over" and a prompt "Press space to continue" for at most 5 seconds before fading through black to the title screen.
• Victory Screen: Displays "You Win!" and a prompt "Press space to continue" until the player presses space, when it fades through black to the title screen.

First of all, nice clean design document. Covers the top level of the design nicely, and makes some effort at explaining the finer details of some of the areas.

I would expand on each of the areas that you have only hinted at, to make the deeper level more complete. For example :
Monsters: Each monster is vulnerable to at least one weapon and is blocked by at least one type of armor.
-Give a reasonable list of types of monsters, their difference from one another, anything significant about them etc.
Or
Explain exactly how the traps work.

So you're definitely on the right track, just some areas need as much explanation as you've given to say the doors.

More importantly though, your design lays out the potential for your game. Put some time in here to dream up whats going to be fun/exciting/different about your game, a reason why someone would choose to play even if the graphics are poor, there is no sound etc.
The story is nice, and no doubt playable, but its not original. You could mix it up a bit... switch the roles of humans and dragons round maybe, so it is a human that has abducted the dragon princess and the dragons are looking for a volunteer to get her back. (Is that what spyro is about by any chance, never actually sat down and played it).