Alex Trebek was the host of the second pilot of this show.
It is said at the beginning of every game that the two contestants are matched based on their gaming ability. It was written in the rules that tanking (or intentionally doing badly to be matched up with a lesser contestant) would be recognized and would be grounds for disqualification. Some contestants were actually disqualified for such practices.
Mark Richards hosted the first 23 episodes before being replaced by Geoff Edwards. Richards was let go for being too stiff and showing no interest in video games.
Geoff Edwards never played video games when he was offered the hosting job. He spent time in local arcades and reading gaming magazines to get familiar with them. Not only did he become a fan, he continued playing video games as a hobby up to his death.
Contestants were given a list of 10 games and had one week to practice and play them before their taping. Of the 10, 5 would be selected to be played for their episode.