That same dichotomy is what faces StarCraft II fans. It's going to appeal to two primary groups: hardcore StarCraft devotees, and people who haven't played a PC game since grade school, but can't resist the hype and the Blizzard pedigree. The first group is sewn up; we don't need to mention them anymore. The second group, though, is huge -- and no one in it "wears shoes." That is, no one in it is a fan of real-time strategy games, let alone PC gaming in general. So, either SC2 an impossible sell that can never succeed, or it's going to convert tons and tons of gamers into series addicts.
To nobody's shock, I'm sure, SC2 is a machine more well-oiled than the Gulf of Mexico: Everything that you know from the original is here, with little in the way of significant changes, but much in the way of tweaks and polish. If you've been playing StarCraft uninterrupted for these 12 years, you'll be able to transition directly to SC2 without batting an eye. However, if you're new to the series, the extensive tutorials (both before and during the single-player campaign) will familiarize you with most of the mechanics.
If you're reading this, though, you're probably already at least somewhat familiar with the mechanics here. SC2 is as old-school and as straightforward as an RTS can get. Part of this is a function of Blizzard not wanting to fix what ain't broke, but part of it has to be chalked up to lack of imagination, too. Each of the three races plays identically to the way it did in the first game, with the Zerg being the "rush" race, the Protoss being the "superweapon" race, and the Terrans being the "versatile" race -- to put everything in "RTS standard" terms.
No matter which race you play, though, you'll do essentially the same stuff: build a base up from a single command center, gather a bunch of resources, tech up to the units you want to build, build those, and put your cunning plan into action. Multiplayer offers a huge bevy of possible tactics, mostly because the races are so damn well-balanced against each other. Indeed, as you play more and more multiplayer matches, you'll realize that multiplayer SC2 is more like a match of Street Fighter II than a match of Company of Heroes. Both SF2 and SC2 require good players to try to anticipate their opponents' next moves (making intelligence-gathering absolutely critical), preparing a counter-strategy, and then making the most of any openings they get to slam the heck out of the enemy. How fast you can click and how many actions-per-minute you can bash into your keyboard are, of course, major factors for pro gamers, but the more dilettantish among us need not worry overmuch about such stuff.
StarCraft II does an absolutely fantastic job of encouraging you to make a plan and execute it. It doesn't have to be a clever stratagem, and it doesn't have to be some fancy-pants multi-part scheme -- it just has to work. This clever sort of straightforwardness is what separates a traditional model like SC2 from some of the newer RTS setups (say Warhammer 40,000: Dawn of War II or World in Conflict) -- amateurs can enjoy it just as much as experts can on a metagame level, even if their actual skill level is considerably lower.
As for the single-player campaign, it's a bit less inspiring, mostly because of the extremely shallow learning curve. One can only withstand so many missions in which the game trickles out a single frickin' new unit at a time; once you get about halfway through the 29 missions, though, things start to pick up. And by the final 10, you've got yourself a decent challenge. The game intersperses each and every mission (and the downtime between them) with more dialogue than The Matrix Revolutions -- although, unlike that piece of crap, SC2's is thankfully optional. The story ain't bad, either -- kind of a conglomeration of Battlestar Galactica and a really good yo' momma joke -- but remember that you'll only get a third of it here; two forthcoming expansions will (eventually) finish the saga.
So, for those of you reading this -- those who are RTS fans but not Blizzard fanboys, those who are interested by the hype but not outright swayed by it -- is this game worth your 60 buckazoids? Yeah, it is: the multiplayer is so smooth, so challenging, and so much plain-old-fun that I can only think of one RTS I ever played that is outright better. The single-player is weaker, in many ways, than that of other RTS titles -- but hey, you don't have to play it, after all. And so, the line you've all been waiting for: Yes, Blizzard has indeed done it again. Now buy some effin' shoes!