So, nobody has started a ME3 thread here?
I find that very odd, so I think I'll remedy that!
This was too good to pass up; I pre-ordered and hit the ground running at roughly midnight Tuesday when the game released.
First impressions, wow, the game really starts with a bang! I don't want to give spoilers, but you're given a few calm moments and then there's running, explosions, running, shooting, and a "barely got out of that alive!" rescue and that's within the first 10 minutes!
Storyline-wise, this game is absolutely epic. No more mystery, no more "okay, so what's going on here...?" it is more like "Okay, we need to KILL these things, let's amass the largest freaking army anyone's Ever seen!" and right from the get-go, you're doing ridiculously awesome things, getting people to work together that hate each other... it is just so EPIC!
Gameplay-wise, it is a lot like Mass Effect 2, but yet they brought back some elements from 1. Soldiers can now use SMGs (never did understand that back in 2, why they couldn't), but yet you gotta watch what weapons you put on, because if you weigh yourself down, you're going to be finding it harder to use your abilities (the more weight you put on, the slower your abilities recharge). So, more guns = a lot more shooting, but a lot less power usage and less guns = less shooting, but more power usage.
Your character can now do awesome rolls, jumps, slipping around corners to evade enemy fire, but then the enemies have picked up a few new tricks, such as guys with huge metal shields that are hard to take down with simple gunfire unless you're a good shot or you got the right kind of powers or squadmates to help you kill the guys.
Melee fighting is better than it was, with new high-damage melee strikes, and you can even assassinate people if you can sneak up on someone and be within melee range while still in cover and undetected; it is a one-hit kill if you manage to pull it off!
And last, but not least, the War Room. A lot of people talk about this and so will I: everything you do (well, nearly everything) contributes to the war effort and it is a complex system. Basically, help people = they help you in the war. Get as many people as you can!
Also, there's a Multiplayer aspect to this game, that helps your Single-Player campaign, but I've not tried it yet so I can't comment. I've read a few things about it that makes it sound so farking awesome.
So, in closing, I've played about 10-15 hours now and I'd have to say... wow. I was trying to imagine how the game could possibly be better than the last one, I never imagined it would be this awesome.
What is even better, is that it has some really nice graphics, some awesome scenery, even in-game rendered cutscenes, and this 4 year old computer can handle it just fine. I've not seen a single instance of FPS drops or anything of the sort whatsoever. The loading times... what loading times? The game loads even faster than ME2 did! Whether you are first starting the game up, or you're transitioning between areas, the worst loading time I ever experienced was ~5 seconds.
In closing: 9.9/10. Easy.
If you like Sci-Fi, I highly recommend this (though you might want to play the first two in order; importing your saves from the earlier games makes the gameplay experience that much better).