In addition to creativity (something original in the gameplay/design), I'd say approachability. A game can ultimately be very complex (or not), but it's essential that it eases you into it, introducing features and elements gradually (long-winded tutorials don't count). It should be fun to play in the first 60 seconds. Too many games overwhelm the player with too much to learn up front. They start out as work, and don't get fun until later. The majority of players will bail on it before then.
As a developer, it can feel like a waste of time to spend all that effort on specialized first levels, and making features (and corresponding interface elements) able to be procedurally enabled and disabled. After all, the player will only do that once, then spend the majority of their time on the "real" gameplay with all features in place. But all experienced players of your game start out as first time players, and if you lose them there, they never see the rest of the game.
In addition to creativity (something original in the gameplay/design), I'd say approachability. A game can ultimately be very complex (or not), but it's essential that it eases you into it, introducing features and elements gradually (long-winded tutorials don't count). It should be fun to play in the first 60 seconds. Too many games overwhelm the player with too much to learn up front. They start out as work, and don't get fun until later. The majority of players will bail on it before then.
As a developer, it can feel like a waste of time to spend all that effort on specialized first levels, and making features (and corresponding interface elements) able to be procedurally enabled and disabled. After all, the player will only do that once, then spend the majority of their time on the "real" gameplay with all features in place. But all experienced players of your game start out as first time players, and if you lose them there, they never see the rest of the game.