FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
Avoid Conceptual Non Sequiturs
At the beginning of the first level of James Bond: Tomorrow Never Dies, the player, in the persona of James Bond, sneaks into an enemy military outpost armed only with a pistol and faces numerous Russian guards; how many, he doesn't know. If he blows up some of the oil drums scattered somewhat randomly outside the outpost, he will find medical kits hidden inside, which he can use later to restore his health when wounded.
Hiding medical kits inside oil drums belongs to a class of design errors, usually made at the level design stage, called conceptual non sequiturs—game features that make no sense. No sane person would think of looking in an oil drum to see if a medical kit might be hidden within. Furthermore, any thinking player would reason that if he's trying to sneak into an enemy military installation armed only with a pistol, causing a loud explosion right outside is not a good idea; several dozen people will come running to see what made the noise. He would further assume that any medical kit that was inside an oil drum when it blew up wouldn't be good for much afterward. Consequently, a reasonable player wouldn't blow up the oil drum and wouldn't get the benefit of the medical kit. In other words, the game punishes players for using their brains. It's simply poor design.
James Bond: Tomorrow Never Dies made the mistake of copying a 20-year-old cartoon-game mechanic—resources hidden in odd places—into a realistic game. A realistic game assumes that players can count on certain similarities between the real world and the game world (oil drums store oil, not medical kits; explosions destroy things rather than reveal things). No flight simulator bothers to explain gravity, for the same reason. The player of a realistic game expects the assumptions he makes in the real world to be valid in the game world. By violating these expectations with a conceptual non sequitur, James Bond: Tomorrow Never Dies became considerably harder for all but an experienced gamer who already knew the conventions of cartoon-style video games.
In short, avoid conceptual non sequiturs in realistic games. They discourage new players and make your game unnecessarily hard without making it more fun. Remember the principle that level designers should reward players for using their intelligence, not punish them for it.
