Please see above title for explanation about why I haven't posted in a while.
Dear god, this game is good. I won't blink if it's still on "top 5 games of the year" lists even in a 2010 that promises Starcraft 2, Heavy Rain, Final Fantasy 13, Bioshock 2 and a new Fallout.
I skipped the original Mass Effect because usually that type of spacefaring Sci-Fi doesn't interest me. But so many people I respect were saying so many good things about ME2 that I had to see what all the fuss was about this time around. Not wanting to sink the money until I was sure, I bought the original ME1 from Steam first for about $25.
It was a blast. The gameplay was basically a stripped-down Dragon Age (made by same company, actually) with more action-oriented combat. Sure, I was annoyed by the same things everyone else had been - elevator rides, the inventory mess, and the fucking Mako - but I loved the game all the same. My expectations were shattered as I discovered an intriguing and mature galaxy full of interesting stories and alien races to meet and mate with. I plowed through it in a few days, and had purchased the sequel off Steam before the credits were even done rolling.
Mass Effect 2 blew me away. It simplified the game in the most pleasant ways, all while somehow keeping it from getting simplistic. There was no more moon rover, no more long elevator waits, and the inventory was replaced by an elegant but fun upgrade system. And it continued the original's process of getting me attached to the characters and to my Shepard, which is no mean feat.
But the real superstar is the combat system. It's a cover-based third-person shooter in the vein of Gears of War (which I've never played) that adds in RPG elements like castable abilities and leveling. The gameplay is addictive, and I've found myself playing side missions just to get more time with the combat. That has never happened in an RPG before in the history of ever. It's just . . . it's just a joy to play.
I think one of the keys is that Mass Effect 2 never gets boring. There are only three things ever happening: either you are engrossed in the shooter gameplay, riveted by an incredibly epic cutscene, or involved in a satisfying or thought-provoking interactive conversation, all while surrounded by very pretty graphics, shockingly good voice acting, and excellent music. You are never sitting around bored. Gush, gush, gush!
[update] OK, it does get boring at one point: gathering resources from planets. You explore galaxies and scan planets for resources, but the scanning is super-slow and you have to do a ton of it for each upgrade, all while constantly replenishing your probe supply. And this is not optional because you need the minerals to buy upgrades. The hacking and bypassing minigames are also kind of tedious, though not as bad as the "frogger in a circle" known as ME1's manual bypass. [end update]
From someone who was raised on Final Fantasy instead of the PC RPGs like King's Quest or whatever, Mass Effect feels to me like the heir to the FF throne. While FF stays too traditional - sitting in the same rut and never seeming to evolve - the Mass Effect series is just chock full of new ideas and improvements while laying claim to the FF tradition of cinematic awesomeness.
Bioware are masters, and in my opinion, Mass Effect 2 is their masterpiece. I will certainly be writing much more about this game . . . after I finish my third playthrough. I can't seem to tear myself away.