We claim the ornamental design for a portable game device, as shown and described.
FIG. 1 is an upper right front perspective view of a portable game device showing our new design in a closed state;
FIG. 2 is a lower left rear perspective view of a portable game device showing our new design in a closed state;
FIG. 3 is a front elevational view of a portable game device showing our new design in a closed state;
FIG. 4 is a top plan view of a portable game device showing our new design in a closed state;
FIG. 5 is a rear elevational view of a portable game device showing our new design in a closed state;
FIG. 6 is a bottom plan view of a portable game device showing our new design in a closed state;
FIG. 7 is a right side elevational view of a portable game device showing our new design in a closed state, the left side elevational view being a mirror image thereof;
FIG. 8 is an upper right front perspective view of a portable game device showing our new design in an opened state;
FIG. 9 is a front elevational view of a portable game device showing our new design in an opened state;
FIG. 10 is a top plan view of a portable game device showing our new design in an opened state;
FIG. 11 is a rear elevational view of a portable game device showing our new design in an opened state;
FIG. 12 is a bottom plan view of a portable game device showing our new design in an opened state; and,
FIG. 13 is a right side elevational view of a portable game device showing our new design in an opened state, the left side elevational view being a mirror image thereof.
The broken lines shown in the drawings are for the purpose of illustrating an environment for the claimed designed and form no part of the claimed design.