I'll just chime in with my opinion.
Story-wise, graphics-wise, and generally overall, I'm very happy with this game. I think the voice actor's performances are just a shade better than in the first game, the story is moving the overall arc along quite nicely, and the graphics have been tweaked just enough to be an improvement. I also don't mind the "cover" combat system; while taking cover might have been taken from Gears of War, the old adage "if you're gonna steal, steal from the best" comes to mind.
However, having said that, I think there are some pretty big issues that need to be addressed, and as TC says, hopefully BW monitors these boards and will take notice of their fans wishes for ME3. So many people have complained about these issues on the Mass Effect 2 board at GameFAQS that in the six days since the game was released, the topic I originally posted the following views in - which I did on January 26 - has been locked from additional posting. And there are over 190 pages of topics from 1/26 on.
- The Thermal Clips BS. Come on, BioWare, what is up with that? In-universe, you go from being able to set up your weapons so that not only do you have infinite firing time but pretty much the only way they'll overheat/be useless is if you get tech attacked(ME1), to just having stock weapons with no customization and now you can for all intents and purposes actually run out of ammunition?(ME2) This seems like one of the biggest steps backward technologically I can envision. And can someone explain to me the logic of cryogenic ammunition making your weapon overheat?
- Character level up change. So, you now have...five, maybe six areas to level up your characters? And the points needed to do so increase exponentially? This seems like an arbitary decision for making the game more difficult. What was wrong with ME1's system of "each point of increase costs a point"?
- Fuel for flying the Normandy. Okay, I get that it's twice as big as the old Normandy, and I get that you're not in the "Grand Mass Relay Central" part of the galaxy. And if you want to have the ship burn fuel, that's fine. But a 1000 unit fuel tank? And it takes over 400 to go the tiny distance from Omega to Saharabik? Very annoying and very unneccesary.
- The display font. Come on, BioWare. It seems like you tried to make it as little as possible for no justifiable reason. What was wrong with the font size from ME1? It's like you went from a 12 to an 8.
- The "Universal Power Cooldown". Part of the reason people liked playing as Vanguards, Adepts or Engineers in ME1 was the "rapid-fire" usage of powers. But now using one power prevents you from using any others? Even with the shorter cooldown times, this seems like an unneccessary complication.
- Not being able to equip your party from the Start Menu. That gave you easy access to everything you had in your inventory, and if different enemies popped up in the middle of a battle, you could switch out ammo/armor upgrades on the fly. Far more useful than the limited customization ME2 restricts players to, which is made worse by only being able to do so on the Normandy or in mission locations that are few and far between.
- Not being able to customize your party's appearance. Granted, in ME1 all you could do was change their armor and put on/remove their helmet, but that's more than you can do in ME2. Okay, these are highly trained operatives, but they're going on a suicide mission and none of them care if they're wearing anything more durable than cotton?
- Speaking of which, why can't Shepard toggle the Terminus and Collector helmets on/off? Although I admit this is more of a personal annoyance.