While being notable for it's story telling and engrossing combat, Mass Effect is also filled to the brim with missions from the main story down to simple and not so simple side quests. From something as mundane as collecting data for a scientist, to a side quest that, if you decide, can help you on your main quest. I found myself drowning in side quests just 10 hours in. Mass Effect is a game that you can reap as much as you decide to put into it. Spend time researching different alien species in the codex on the main menu screen, do as many side missions as possible or just go along straight to the main story -- the choice is yours and ultimately each gamers experience is their own.