If you are a previous fan of Mass Effect, this is the game that you have been waiting for. If you love a good space faring story (Battlestar Galactica, Star Wars, Star Trek, etc.) this is the game that you have been waiting for. This has been called the Empire Strikes Back of the Mass Effect series and in turn, it may be the best game of all time. Something I read on Gizmodo puts it better, "Mass Effect 2... transcends to science fiction that you can play."
The events of Mass Effect 2 take place two years after the events of the prior entry in the series. The Collectors are abducting human colonies and you are charged with taking on the suicide mission to stop them. Throughout the game you will assemble a team in order to stand a fighting chance against the Collectors and assembling that team takes you to the far reaches of the galaxy.
The majority of the experience takes place in the middle of the Terminus Systems - only previously mentioned in ME1 - so the subject matter is far grittier and the subject matter is significantly darker. The story that we are given in the Mass Effect series is some of the greatest because the information - the Mass Effect bible if you will - was created at the same time and it allows for a lack of plot holes. Most science fiction stories that we encounter have been told over many generations and Mass Effect has had the luxury of being told over the span of one - let alone one platform.
The story could not exist without its characters and the characters that you encounter are nothing less than gorgeous, gritty, deadly, and charming - there is everything to be said about the writing that surrounds them. Depending on your play style you will have your favorites and there will come a point where it becomes upsetting that you can only take two of them with you on each mission. Each character has a rich back story that will leave you feeling as though you know each one personally. I personally became attached to many characters and one would be a surprise those whom have not yet dipped their toes into the ocean that is Mass Effect 2. At the games end, though I did not take him on a wealth of missions, Thane had become my favorite character.
The combat - this time around - actually feels like combat. In ME1 we were given combat, based on dice rolls (To the naysayers: I know this to be a standard RPG element) that was supposed to feel more like a third person shooter. In its successor we are given complete third person "control" and are still, in the way of an RPG, if not more than the first game, encouraged to deploy our squad and continue doing so throughout the remainder of the fight. You could also set menu options and rob yourself of this experience having the computer take control of your squad. Everything from the controls to the way actual combat takes place feels fluid and perfect. It is a third person shooter, much like Gears of War, inside of an RPG. Having compared the combat to Gears of War, ME2 ends up missing a few bits. You cannot move from cover to cover and I also noticed that there is no animation for turning around a corner. These things never get in the way of gameplay but they will be welcome additions in Mass Effect 3.
The combat is not the only improvement on the first game. There is no longer micromanaging of weapons and armor but instead a simple upgrade system that allows for everything to be upgraded as you collect or buy research items. The minerals that you have to mine throughout the game (again another fluid system) fuel those upgrades. The mining system no longer involves landing on the planet but instead scanning and sending down probes. It is only annoying some of the time, especially when you are scrambling to look for Element Zero and Platinum.
Another change, subtle as it may seem, are what I like to call "Action Moments". These moments allow you to either take a Paragon or a Renegade action in the middle of certain conversations and they vary depending on how you are choosing to play through the game. They involve a left or right trigger press (left = Paragon; right = Renegade) and it dramatically changes the way that scene would have progressed if you had pressed nothing at all.
All the revamps and additions to Mass Effect 2 are welcome and they all feel like the team at Bioware were listening to what we had to say.
There are not enough good things that I can say about Mass Effect 2 but one is that I will be playing this game, over and over, for years to come. I still plan to return to ME1 in order to create more "Shepards" that I can drag over to ME2. There is not a soul that should go without this gem of an experience. You should not be one of the few that choose not to play. Join the team and, "Fight for the lost."