Let me start by saying personally I was not a fan of the first or second installments of the Mass Effect series but Mass Effect 3 is a different story. I have never jumped into a game and within the first 5 minutes said to myself "me and sleep are about to be no longer acquainted" but with ME 3, my first play sessions lasted me about 9 hours and I still wanted more, the story is probably the best in a game to date and the combat can be either simple or in depth depending on your cup of tea, personally I love finding which biotic combos work best for different enemies and finding out when using a gun here or nova there will be more effective. Next is the multiplayer, I wasn't very interested in it until I started playing it, it has a much more satisfying feeling than horde or zombies ever will, it's an actual challenge which is pretty hard to come by these days as game dev's are focusing more and more on casual players. All in all with all of the generic titles that have been getting released lately it's a great change of pace and will keeping you playing for hours, I only wish there were more hours in the day so I could grind all of my characters to max rank.
The single player campaign offers alot of replayability! Bravo to Bioware! The multiplayer is a nice touch also especially with fans of gametypes like (Horde from GOW3). Highly recommend this game even if you havnt played the first two games of the