An example portable, handheld game console includes a main body incorporating a first display screen, and a cover body incorporating a second display screen. The main body is hingedly connected to the cover body along adjacent forward and rearward edges, respectively, such that the cover body is movable between closed and open positions. The main body is provided with a plurality of control buttons and a pair of game card slots for receiving game cards of different dimensions. One of the game cards is substantially square and comprises a substantially flat card body having a plurality of electrically conductive terminal strips adjacent the forward edge. One of the side edges of the card has a single continuous step configuration along substantially the entire length dimension of the card. A first notch is formed in a first forward corner of the card where the forward edge meets the other of the pair of side edges and a second notch is formed along the other of the pair of side edges, between the forward and rearward edges.