I was thinking about this a few days ago but here's a few things I think people should know about ME2.
-Unless you want to play it as a third person shooter, don't choose soldier class. Soldiers are soldiers. Their guns and such are overpowered and they don't get some of the cool abilities that other classes get. Don't get pissed about being stuck using guns if you choose the class that specializes in guns!
-Bump the difficulty up a notch. The game is a breeze on normal. On harder difficulties, you'll have to use your mind. You'll have enemies that react smartly, will use barriers and shields to protect themselves, will summon drones and back up, and will actually try to use magic against you. It makes the combat that much more fun.
-If you're not using soldier and you've kicked the difficulty up at least one level, you're set. Now, gaining levels will mean something because you'll be concerned about how quickly you can regenerate your biotic powers, how much damage your armor can prevent (there IS a difference in armor--everything from how fast you can use power to how fast you run to how much damage your weapons deal out). You'll care about what kinds of weapons you use because certain weapons and magic work better against certain enemies.
-You can combine powers. Try levitating an enemy and then hitting them with "warp" to send them flying. Try freezing an enemy and hitting them with "concussive shot" to shatter them like glass. It's pretty cool. And each of your team members has their own set of powers. Some can boost the firepower of the team or boost the team's defense in certain areas. Some will inflict "Pain" on a foe to cause them to slowly lose energy for a bit. Some can teleport behind the enemy or use a cloak (Kasumi). Some can take control of enemy robots and make them fight on your side (Tali). Some can blast fire to incinerate enemy armor shields and others can use "warp" to take down enemy barriers. Of course, using a gun will work on easier levels but, on a harder level, there's a huge difference.
For example, on default settings, if you encounter a Krogan, you can just shoot him to death. On a harder level, they'll charge at you in a rage. You can shoot them but their energy regenerates quickly. On top of that, they pack shotguns that pack a powerful punch AND some of them can use biotic energy. You'll have to freeze them to stop their attack or set them on fire to stop them from regenerating energy. They can't be levitated and flung through the air until their armor or barrier is taken down. Requires a little more thought, doesn't it?
-Don't rush through the game. It may seem boring but scanning planets is important. It will earn you vital minerals to improve your ship, your team, your armor and your weaponry. Talk to everyone. The more you do, the more you'll see. Make choices based on how you would react in that situation. If you're bad enough, you can intimidate people into getting the result you want in a particular dialog. If you're good enough, you can influence a positive reaction from people.
-There's going to be some tough choices. Do you let a villain get away or do you let his victims die? There are usually no wrong answers, but these decisions are important in forming which direction your story will take and who's going to be around to see it. People I let live in ME1 popped up in ME2. There are quite a few instances where this should happen in ME3. Choose wisely.
