This screenshot is from my 2nd freeware game called X's & O's Football. The game was written using Visual C++ 6 and the DirectX 8.1 SDK. Even though the game looks 2D it does use Direct3D to render all the graphical elements as flat polygons. Some polys are textured, such as the yard-line numbers, and the rest are simply unlit flat shaded quads. The game also uses full-scene anti-aliasing if supported by your video card and requires a 6-button gamepad or joystick to play. It supports 2 players but only on one machine using either the same usb controller (offensive player only) or 2 usb controllers (offense and defense). AI in the game is pretty basic with the defensive players doing whatever it takes to get to the ball (ie. a straight line approach) and the offensive players trying to form an arc in front of the ball carrier to block the defense. Collision detection is done using bounding spheres around the players and the ball. You can pick one of 5 plays for offense (and defense if multiple controllers are used) which include passing plays, punts and field goal attempts. Games are timed at 15 minutes and a 20 second play clock keeps the game flowing.
Download the 1.5mb game at http://www.lesbird.com/default.htm