Mass Effect 3? I'll do the whole series.
Mass Effect - Plot synopsis: http://masseffect.wikia.com/wiki/Storyline
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Story: The story is great and the character's well written, although some of it seems forced on you.
Gameplay: The cover system is wonky, and doesn't work well. which would be fine if it wasn't the main point of combat. find cover, kill things, move on. The weapon overheats can be frustrating, especially when you use a sniper. but overall the gameplay is fun and interesting.
Graphics: the graphics work well enough for the type of game it is, but i feel like the character creation is poor, and you can never get your shepard to look like he/she isn't horribly disfigured.
Rating: 7 / 10
Mass Effect 2 - Plot synopsis: http://masseffect.wikia.com/wiki/Storyline_II
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Story: the story in this one is very good, and the character's are once again believable. the story can feel a little tedious though. it also is a nice change of pace to be working for the good of humanity, but with an air of danger working with Cerberus. Also, Martin Sheen.
Gameplay: the cover system get a slap in the face and is told to straighten up, so it works much better, with a prompt to enter cover instead of walking at a wall. The thermal clip system Is better than the overheat system, but can be frustrating when you can't find ammo. the addition of heavy weapons in lieu of grenades is an interesting choice, but saving up the ammo to use the M-920 Cain Mini-nuke was very satifying. However the lack of weapon and armor variety has always disappointed me, but is rectified with DLC. Also, armor customization is a welcome addition.
Graphics: Same as 1 but with a larger Palette and more shading.
Rating: 8 / 10
Mass Effect 3 - Plot synopsis: http://masseffect.wikia.com/wiki/Storyline_III
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Story: Fantastic! Except for the ending. the ending was written poorly, as i'm sure you've heard about at some point, which prompted a huge fallout (< theres your review Syko. jk I'll do one after this.) of anger from fans, so much so that Bioware had to release a free DLC extending the ending. even with the DLC i still don't like the ending. A good story keeps you guessing until the end, than reaches a reasonable conclusion, ME3's ending did not make sense. This is a big black mark on a great game
Gameplay: Great. the game is cleaned up and the controls are tight and responsive, the new melees are fun and the selection of weapons and armor is wide and expansive. it's easy to lose track of time playing the story and multiplayer. Truly a rare case of sequels getting better every time.
Graphics: A Much needed upgrade, but still not fantastic.
Final rating: 9.2 / 10
Overall rating: 9 / 10
The links contain a full summary of the games and any books that go in time with the plot.
Up next will be Fallout 3 / New Vegas.