'Each individual level is really its own concept, you have different mechanics you have to learn for each mission as well as something internally we called 'storymode.'' 'We did things that change the micro mechanics and in the single player game we’ve done a lot of things to make every mission different too,' he explained.

The abilities and strategies introduced by those fresh units may carry over into the level concepts as well, which Sigaty said will vary from map to map. 'We're making it different beyond just changing some units, there are around 40-percent different units per race dependent on which race you are playing,' the game's lead producer Chris Sigaty told PCGZine. In fact, the game's armies change by about 40-percent as compared to the franchise's first title, according to Blizzard. ' StarCraft 2' beta players have been hard at work testing the game's multiplayer experience over the last month, but when the full version drops this summer there are going to be a lot of new faces showing up. Limiting the number of units per faction keeps the game from having functional redundancies in the armies.'

'As a matter of fact, the development team has mentioned several times that they’ve purposefully resisted the urge to just add on top of the 'StarCraft' armies – a general principle has been that for every new unit we added to the multiplayer game in 'StarCraft 2,' we remove one of the original ones. UPDATE: Blizzard reached out with some clarification about the reported 40-percent change in factions for 'StarCraft 2.' 'The number of units per faction is not growing by 40-percent in 'StarCraft 2,'' Blizzard Entertainment public relations manager Bob Colayco stated.

Starcraft 2 new race