9) History
BioWare are the undisputed kings of RPG storytelling, and it shows. Mass Effect has incredible attention to detail to help make the word as believable as possible. In the menu system is a codex and encyclopedia (all in spoken dialogue) that will fill you in on the back stories of planets, the alien races or basically anything that you feel you need more information on.
10) Massive effects
Absolutely huge in scope, ambition and choice, Mass Effect will give you plenty of game for your money. From the galaxy map, you can choose to explore hundreds of star systems - some will have planets you can land on and side-quests you can take part in, others will hide special items, while some are there simply to look gorgeous or offer some other point of interest. Even better, because you can play in so many different ways, because the choices you make will alter the outcome, you’ll be replaying this for months to come.