The middle part of a trilogy is generally the hardest to nail, it will neither contain the wonder of the first or the payoff of the last. Blizzard have an advantage with this structure though. Both the original Starcraft and it's expansion, Brood Wars, played out in three acts: Terran, Zerg and Protoss; which is exactly the same format that the Starcraft 2 trilogy will follow. Traditionally the Zerg sections of these older games have been considered the weakest although this is more to do with their lack of characters rather than doing anything wrong with the gameplay or story.
So, the hardest part of a series coupled with only moderate success in this are in the past. How does HotS (Heart of the Swarm) shape up? Well, for starters, the issue with characters has been soundly resolved. The protagonist of the campaign is Kerrigan, a character the player will have instant sympathy with if they've been following the series. After the opening mission or two this is expanded into a few Zerg each with there own personality. This was quite a big step for Blizzard to make canonically but adds a huge amount to the overall fun of the weighty single player campaign, which clocks in at over 20 hours if all 27 missions are completed (I'll admit I'm far from an RTS pro though).
The draw of the story is heightened by the brilliant voice acting on show, with geek goddess Tricia Helfer (Battlestar Galactica's 6) playing Sarah Kerrigan, as well as a host of other well know names such as Frank Welker (Transformer's Megatron) and Steve Blum (Spike from Cowboy Bebop). The whole game is fully voiced including all the in game prompts adding an extra layer of polished immersion. It goes without saying that the CG cutscenes are a wonder to behold and rival what would be used in full film production.
The format of the game itself is the same as the first part of Starcraft 2, WoL(Wings of Liberty), where missions are taken on from a kind of hub that allows the player to interact with crew, look at upgrades and do smaller sub missions. There's no alternative paths in this campaign though, the only choice the user has is what upgrades to give units if they decide to do the mutation missions. While this could be seen as taking away from some of the replayability present in the first part of the Starcraft 2 saga, in reality all it means is that you don't have to go back and play through a few alternate missions once that the story portion of the game is complete.
It's worth mentioning that while play time, production budget and indeed upfront cost may make this seem like a stand alone product, you will need to own Starcraft 2 Wings of Liberty to play. Having installed HotS on several computers I can confidently say that it essentially reinstalls WoL then another 4 odd gigabytes on top. Play itself requires the usual battle.net account login stuff which acts as cloud storage for saves, handily enough.
While it's safe to assume that the player will have completed WoL before starting this (the story won't make a lot of sense otherwise) for arguments sake it's best to cover how the new game plays. It's much closer to Warcraft 3's RPG/RTS hybrid play than a straight up real time strategy experience. While there was some of this in WoL it's much more prevalent in this game with Kerrigan being in almost every mission and another hero unit being present on the odd occasion where she is not. As she levels up she unlocks new abilities as well as becoming stronger and these skills can be reconfigured before every mission allowing you to try out all the treats on offer. The players army can be divided up into smaller groups using the usual hot keys as well as new UI based buttons and the whole army can be selected with one click.
Suffice to say this is the most sublime RTS interface yet produced by any developer, honed by hundreds upon thousands of competitive multiplayer matches played worldwide. It's little wonder why this is one of the biggest completive video games in the world. Indeed, for professionals of the series the single player can be seen as a in depth tutorial with very pretty cut scenes. The game contains a huge amount of extra content to get players new and old up to scratch with all the armies and their new units, teaching them to optimise different stages of a battle turning it into a fluid experience of back and forth.
No one needs to worry about owning beastly computer to play thanks to the wonderful engine scaling. While turning everything up to 11 will still require quite a bit of horse power, pretty much any system made in the last 4 years or so shouldn't have any issues running the game on lowered settings. There's also good news for Mac gamers because as usual Blizzard have a OSX client right out the door even if it doesn't perform particularly well compared to Windows (at least at time of writing). It's also worth noting that I suffered some issues with my profile that resulted in me having to redo three hours of gameplay. It only happened once but there may still be some kinks to iron out with battle net.
I've been racking my brain trying to think of something negative to say but I came up short. It's almost like blizzard have polished it to the point of nothing being outright bad about it. Even that comment sounds overly harsh. The only real downside to what's on offer here is the brick wall new players will find themselves having to overcome to be competitive at the multiplayer. The match making is good but the higher level of play some people bring will take hundreds of hours to get close to no matter how much time is spent training and playing against similarly skilled foes. This is only a fairly minor concern though, there's still the brilliant campaign to enjoy, single player and coop side of the multiplayer against bots and a challenge mode for the more daring.
As an overall package then, this game offers something for everyone and even if it was only purchased for one facet of the overall experience, you will find excellent value in the box. The only major downside I can see is that it'll be at least another year before the closing part of the saga will be available. If it's to the standard of this game and the one before though, the wait will definitely be worth it.