Penalties are rare and are usually only enforced in the most egregious cases, such as serious injuries or blatant pass interference.The game ends when a pre-determined number of touchdowns or points has been scored, or an arbitrary time is reached (for instance, dusk or the start of school).In order to achieve a series of downs, backyard football requires the team with the ball to complete two passes or reach a certain point on the field.Few games include enough people, or the proper equipment, to run a chain crew to maintain the 10 yards familiar in most organized leagues.Many versions skip this process and start the offense at a certain point, similar to that following a touchback in organized leagues.Thus, until an interception or turnover on downs occurs, both teams defend and attempt to score on the same end zone.There can be a rush on the quarterback (commonly called a blitz in this context) depending on the rules set out before the game.Atari's Backyard Football series, on the other hand, is a more kid-friendly game with players including child versions of NFL stars.