Designing Magic Numbers
When designing Magic Numbers, I opted to focus less on technical complexity and more on approachability. I wanted a dice game based around uncertainty (not knowing the results of your roll), but also around hidden information (your opponents not knowing how your roll affects you).
Approachability meant giving players simple tools to work with, and not a whole lot of them. I based the game around a single six-sided die and started with a simple addition mechanic, where competing players would take turns rolling the die to add to their score: First player to x wins. With no decisions being made by the players, the game certainly wasn't fun, but the uncertainty introduced by the die kept things unpredictable, which was definitely desirable and a good start.
I then layered additional rules on top of this basic mechanic. Knowing I wanted players to have a sense of agency in the game, I introduced the abstract idea of "giving" a number, where an undesirable roll could literally be handed to another player.
The question then became, why would any number be undesirable? From this, I decided that at the beginning of the game, each player would roll to determine an "Evil Number" - a value that, when rolled, would revert the score to zero. A player could then give away his Evil Number if he rolled it, but other players could give that player his evil number if/when they determine what it is. To contrast this, I came up with the "Good Number" concept. A surprisingly deep bluffing element emerges from the intersection of these two rules, as players can try and psych out their opponents, while at the same time trying to learn their magic numbers.
The only additional rule to be revised at this point was the goal of reaching a score of 30. After some play testing, it became apparent that players should have to add to 30 exactly, and not go over that number. This slowed down the endgame and in some instances forced players who got stuck to take their evil numbers and start over - a desirable player behavior and one that complicated the inherently simple game.
Does it work? Try playing Magic Numbers with one opponent. Try playing it with five. Some matches end in four turns; some go on for 15 minutes. Strategically, it's not a particularly deep game, but it is, I feel, a fun one, and certainly approachable by anyone with an extra die and a little free time.