Starcraft – Why did mechanical units explode when being fixed by SCVs in Starcraft 2

Focus fire is critical for sniping injured units and for taking down important or high DPS units like void rays, ghosts, brood lords, immortals etc...

But beyond that, it actually worse to focus fire units. Using this awesome map, I have actually tested micro battles with and without focus fire. I have found that 9/10 times any group of units I micro to focus fire just flat out lose to non-micro'd units.

There are two problems with naive use of focus fire. 1) Targeting one unit will most likely cause you to over-kill the unit, which is a waste when you could be shooting at another target. and 2) If your unit is not in perfect range of the target, the unit will bumble around until they are, which means instead of attacking, they are bumbling around.

• Most of the advice to stop Nydus worms applies in general. First of all, you should be keeping an eye on your base no matter which race you are facing, and regardless of whether or not you have scouted a Nydus Network in the Zerg's base. All races have ways of getting units into the back of your base without going up the ramp. Medivacs, proxy pylons, overlords with ventral sacs, warp prisms, blink stalkers, colossi, reapers, etc, not to mention pretty much any air unit.

• Denying vision to the zerg player by harassing overlords should be done in general, not just to stop worms.

• To help detect the nydus worm (and all other threats mentioned in previous bullet), spread buildings out in your base, so you have vision everywhere. Terrans can spread supply depots, protoss have pylons, and zerg have creep tumours, or overlords to spread around.

• Learn the sound a nydus worm makes when it completes. Sadly for us zerg players, the nydus worm announces itself to all players with a loud scream, similar to how everyone hears "nuke launch detected". On the plus side (for us), it only screams as it is finishing. This won't help you stop the worm, but it will alert you that you should be looking for the worm to make sure it's not in your base, or if it is, mobilize some troops to defend.

• In team games, consider using the team colors option for the minimap, so your units are green and your opponents are red. This will make the nydus worm stand out in your minimap more than if you are orange and your opponent is yellow, or some other combo of similar colors.

• Worms don't have a lot of HP, even when they complete. When they are building, a handful of units can kill it before it completes. I just did a quick test; 3 marines starting to shoot as soon as the worm reaches 50% done can kill it just after it finishes, enough time for only a few units to get out.

• Remember that each worm costs the zerg player 100 minerals and 100 precious gas. Each time you kill one before it completes, the zerg is behind on resources. They can also only be building one at a time. (specifically, one per Nydus Network)