In this game you need to collect 34 red remotes, 16 silvers and 4 golds to enter Channel Z to beat the game. Red remotes are collected by beating missions in each level. There are generally 2 silver remotes in each level. One is hidden somewhere in the level and the other is obtained by collecting 120 items. Silver remotes allow access to the 4 bonus levels. Each bonus level beaten nets you a golden remote (so you get 4 in total). With your golden remotes you can finish collecting all 34 red remotes. After this, you're free to go and beat Rez.