Short version: Blizzard continues to release games when they are ready.
Long version: OK, I'm not the most impartial reviewer here. I was predisposed to absolutely love this game after how much fun I had with both the single- and multi-player parts of the original Starcraft, as well as every installment of the Warcraft RTS games. And guess what? I absolutely love it. I love it so much that I wish I could italicize that last sentence twice.
More after the jump.
I've only completed the first 5 missions, so keep that in mind as you read.
The story is primarily moved along by cutscenes rendered in a sort of in-between engine: fully 3-D world and models (reminded me of Mass Effect 2) that aren't as good as a CGI cut-scene but quite a bit better than just zooming in on the overhead RTS graphics. Once the cutscenes are over, you can't walk around freely in the world, though - it plays like a point-and-click adventure game. This is actually a blessing, because it eliminates the extra, unnecessary steps of walking between areas or even moving around a 3-D world to click on each object.
According to videogame luminary Sid Meier, "A game is a series of interesting choices." Starcraft 2 strips away everything else and delivers concentrated game without the usual filler.
That's a hallmark of the SC2 single-player mode: needless complications are removed. I'm sure there was a version of the between-mission areas where you walked around, but it was scrapped because walking around didn't add anything. Instead, you travel between areas by simply clicking an ever-present menu at the bottom of the screen. Then you'll just appear on the bridge, or in the cantina (complete with holographic nude Night Elf and fully playable "Lost Viking" shoot-em-up arcade machine), or wherevert. You can interact with the environment as little as you want. The game will highlight objects of interest with new content, such as characters with dialogue you haven't seen yet or a TV with a new report, so you don't have to waste any time clicking around looking for new stuff.
Speaking of televisions, Blizzard went out of their way to add optional content throughout these areas. You don't need to click on the characters or the TVs to progress the story, but if you do, you'll be treated to high-production-value, fully-voice-acted, and amusingly-scripted news reports deepening the storyline of our hero Jim Raynor being painted as a terrorist by the douchey Emporer Mengsk (I swear that name must translate as "douche" in Terran). In a humorous running gag, the news anchor continually interrupts the correspondent trying to give him facts, and then recaps every story with a spin about how evil Raynor is. It's a little optional detail that goes a very long way to building the world and making the game feel more fun.
The streamlining carries over into the single-player progression system as well. You get your choice of missions from a star map where all you have to do is click a planet and you launch the mission, which gives you all the benefits of Mass Effect 2's nonlinear planet-hopping without having to waste time tediously flying the ship every step of the way. Each mission unlocks a new unit for your army that you can then use in all future missions and upgrade in between missions. The upgrade system is simple and intuitive, with each unit having 2 upgrades with varying costs. Each mission you complete gives you a certain amount of cash, and you can then spend that cash as you wish on upgrades and mercenaries (uber-units with limited supply-per-mission).
The key thing about the upgrade system is that you can freely choose which upgrades you want to buy, but you will never have enough money to buy them all. Despite its simplicity, it gives you interesting choices to make that you can tailor to your playstyle and influence how you use your army. The system is easy to understand, but can actually lead to a different experience for every player and every playthrough.
The missions themselves are classic Starcraft gameplay. The first two are really throw-aways meant to ease new players into the game, but then it quickly moves into a base defense mission and then a fun and memorable mission where you must escort waves of civilians to a starport while zerg are falling from the sky and popping up from underground all along the route. You can defend certain entrance points, but you also need to have some roving teams to deal with zerg ambushes along the road.
Each mission also includes optional goals. Aside from the side quests the game overtly issues, there are also resource caches hidden throughout the maps as well as zerg and protoss objects that give you research points with each race. As you gather research points, you unlock yet another upgrade tree, Research. Each tier of the tree offers two mutually exclusive options. Again, the game gives you very simple choices, but they are impactful and engaging. They are also fully optional. Even more replay value comes from achievements linked to each mission that add extra challenges, such as completing the mission in a certain time limit on hard mode or destroying enemy bases on missions where that is not the objective.
Throughout the design of the single-player campaign, Blizzard managed to make everything simple and easy to understand while still offering interesting choices that make up the core of a satisfying game. The game is nothing but wheat, and there is no chaff to be found. Bravo. It's a testament to how complexity does not necessarily equal depth or fun. Interesting and meaningful choices give you those things, and there's absolutely no reason those choices need to be obscured just to achieve an appearance of complication. A simple and elegant way of offering interesting choices is actually a better way.
Sight unseen, you'd think that more freedom would obviously be a good thing. But in SC2's single-player mode, Blizzard cleverly pruned out the aspects of freedom that don't really add to the game, and instead focused on delivering content and interesting choices to you in the least wasteful way possible. Every moment is spent making interesting decisions or being entertained, and none of it is spent trying to figure out complicated systems or wandering down 3-D hallways trying to find which door leads to the armory.
It's a brave choice, and one I think some reviewers will lament. But I, for one, love tossing all the rinds and only getting the juice. The sweet, sweet interstellar cowboy juice.