There seems to be a very wide range in the abilities of the winner and runner up bots that might not be noticed by someone unfamiliar with Starcraft. In order of appearance:
1) In the flying units versus flying units match, mutalisks (guys with wings) should have focused the scourges (little 'c' shaped guys) because scourges have about 1/5th the health of a mutalisk, but can suicide to take out 5/6ths of a mutalisk's health. Red ai focused scourges, the other ai didn't, with disastrous results for the other ai.
2) In the match with infantry, the players had medics, which heal other units but can't attack, and marines/ghosts, which can do damage but can't heal each other. One ai moved medics with ghosts such that the medics could actually heal. The other ai just left the medics a mile away from the combat, and got slaughtered. Furthermore, the AIs didn't bother with formations, which meant that half their units spent the entire fight trying to get into range. A precombat formation lets almost all the combat units start firing as soon as the fight begins.
3) The red zealots retreated in the face of numerically superior opponents, while the teal zealots just attack moved no matter how many they had. Teal zealots didn't focus fire, which meant that they lose units sooner, and thus had less damage output compared to red. In addition, red failed to kill the pylons (600hp) powering the buildings (a lot more than 600hp). Neither player built their bases to maximize the number of pylons powering their vital gateways; each pylon usually powered only one building.
4) In the fight with dragoons (orange spider things) versus tanks, the protoss (orange) could have frozen half the enemy tanks with a single stasis spell by sneaking the arbiter (flying spider thing) to the back of the tank formation. Furthermore, the protoss could have focused the science vessel (floating teal circle) that was preventing them from being invisible. It would have been a slaughter if the vessel had been focused, as teal would have had no real way to hit the orange units.
5) In the match between Overmind and Krasi0, the article talks about mutalisk clumping preventing some of the mutalisks from attacking. However, the point of the stack is that when one guy is in range, everyone else is. Also, the attack animation is so fast that for all practical purposes, the flyers can shoot while moving. They use their mobility to get out of range of infantry units, then zoom in to pick off outliers when their attack cooldown is finisihed. In actual competition, the terran player would usually rely on a strategic placement of static defenses and a highly mobile cluster. However, the terran (defending force) built tanks, vultures, and goliaths (mech guys that shot missiles) with the flaw that tanks and vultures can't shoot air, and are thus almost useless versus the mutalisks. The mutalisks spent the second half of the clip shooting tanks rather than focusing down the goliaths volleying missiles into them. The terran AI prioritized repairing tanks as much as goliaths, and didn't place tanks next to goliaths to soak up bounce damage from a mutalisk.
In general, the AI had problem with understanding the priority in a fight. That is to say, they often had no sense of what units are critical to a position or what units pose the most threat. They didn't arrange their units to maximize their effectiveness, and often failed to alter their behavior based on the other party. It's a fun contest, but I'm not sure the AIs could beat a moderately skilled player who understands tactics AND strategy.