In this paper, we test the effect of descriptive "features" on initial strategic behavior in normal form games, where the term "descriptive" indicates all those features which can be modified without altering the (Nash) equilibrium structure of a game. Our experimental subjects behaved according to some simple heuristics based on descriptive features, and we observed that these heuristics were stable even across strategically different games. These findings indicate the need to incorporate descriptive features into models describing strategic sophistication in normal form games. Analysis of choice patterns and individual behavior indicates that non-equilibrium choices may derive from incorrect and simplified mental representations of the game structure, rather than from beliefs in other players' irrationality. We suggest how level-k and cognitive hierarchy models might be extended to account for heuristic-based and feature-based behavior.