Find an Idea
This is probably the most fun step. Before building a game, you've got to come up with a concept. If you're new to game design, it's very important that you start with a simple idea. Starting with a complex game, it's easy to get frustrated or lose hope.
Tip
So how do you know if your game idea is complex? That is hard to answer. If your list for step 4 ("Identify what you do not know how to accomplish") is very long, then you may want to start with another game concept. In the beginning you may not know how to accomplish much at all, which is all the more reason to try to find a simple idea.
When you get your idea solidified, map it out step-by-step, as if you were explaining it on an instruction sheet in a commercial game. Make sure that the game has an objective.
The Idea: Multiplayer 8-ball.
The Object: To knock the cue ball into the player's own set of pool balls (solid or striped) to send them into a pocket.
The Rules:
The game of 8-ball is played on a pool table with six pockets.
There are 16 balls (numbered 1 through 15, plus the white cue ball). Balls 1 through 8 are each a different solid color. Balls 9 through 15 are each marked with a different-colored stripe.
This is a two-player, turn-based, multiplayer game.
Player one uses a cue stick to hit the cue ball into a triangular configuration of the 15 balls.
Player one chooses either balls 1 through 7 or 9 through 15 for his or her own; the other set goes to the other player. The 8 ball belongs to neither.
If you choose to have an alternate method or rule for dealing with some facet of your game, make sure to spell that out, too. In our example of pool, there's a widespread alternate way to assign stripes or solidsthe first player to sink a ball "owns" that style of ball.
Each player takes turns knocking the cue ball into his or her own pool balls to send them into a pocket. This is typically done one by one.
When a player has knocked all of his numbered balls into the pockets, he then attempts to knock the 8 ball into a pocket. If the player succeeds, he wins the game.
If either player knocks the 8 ball into a pocket before he has finished sinking all of his numbered balls, that player loses the game.
If the cue ball ever goes into a pocket, the player's turn ends.
If a player hits one of her numbered balls into a pocket without hitting the cue ball into a pocket, then the player's turn continues; otherwise her turn ends.
If 8-ball were your own original game idea, you would probably want to get into much more detail with the game rules. Writing out all the rules of the game gives you something concrete to refer to later, when you're writing the ActionScript. Even if the rules are relatively simple, a quick, linear reference will probably help you organize your ActionScript more easily. And then, of course, with new and more complicated games, it may be dif-ficult to remember every single rule.
RPGs are like the lure of the Sirens
If you are a novice game developer, do not be tempted by the lure of the role-playing game (RPG). A good RPG is a multiplayer game with a complex story; it loads in graphics dynamically, builds screens dynamically, and makes use of pathfinding, enemy AI, and thousands of screens. A game with that kind of complexityprobably the most challenging type of game project you can take onwould typically take you (and the rest of your team) several months to build. Over the last few years I have encountered many people who have brilliant game ideas for massive RPGs. I have seen dozens of people and teams of developers start with an outstanding idea for a Flash RPG, and only one of them that I know of has finished.