With the Starcraft II beta nearing its end, Blizzard has released one of the biggest patches so far in terms of balance changes. The most exciting alteration is surely the nerf to protoss' force fields: "Force Fields can now be destroyed by Massive ground units walking over them." The change should mean that Thors, Colossi and Ultralisks will become much more important units against protoss. Followers of Aiur will also get a small but significant nerf to their main air unit, the Void Ray. Its range will be reduced from 7 to 6 when the patch goes live.

But while protoss is only receiving nerfs, terrans seem to be getting nothing but buffs. Marines will get reductions to the cost of the Stimpack and Combat Shields upgrades from 150/150 to 100/100. Some commentators have speculated that this means Stim will no longer affect Marauders but this has not been confirmed or denied by Blizzard.

By far the longest list of changes goes under the Zerg header, however:



The zerg changes seem quite extreme but the Ultralisk nerf is probably to counteract the fact that it counters Force Field. However, the fact that the Thor didn't receive similar nerfs does make it a little more confusing. According to Blizzard themselves "this Ultralisk should be able to deal with both mass Marauders and mass Roaches."

Source: Patch Notes | Official Explanation