Game 1 - Most protoss goes for FE and corsairs, and adapts to the zerg. Bisu found that strategy ineffective as the map is 0-4 PvZ. So he tricked Gorush of thinking he went FE while he powered zealots goons and reavers. Very rare play from protoss these days.
Game 2 - the 4 hatchery play was a risk by Gorush. However, bisu did not see the 4th expo and the lair, so he thought gorush was going to power hydras therefore he cannonned. However when he found the 4th expansion, it was too late. The zerg's macro kicked in and he lost.
Game 3 - Before the game even started in the interview Gorush said that this was the hardest map for zergs. He could beat his teammates that played zerg when he was protoss. He said it was that hard. So he tries 2 hatch power muta. And takes 12 expo and switches to hydra. He did a good job of taking corsairs from time to time and distracting them. He went for all-in build, and tried to drop but Bisu scouted it(After the game Bisu said it was just luck, he just wanted to see what the zerg was doing). It was an all-in build, and Gorush knew he couldn't comeback so he gg'ed. However if he attacked Bisu in ground, Bisu would have been screwed since he didn't even have storm upgrade.
Game 4 - It was just luck for Bisu that he FE'd at the same place as Gorush, and Cannon rushed. And all downhill from there. Gorush goes 1 hatch lair, and makes an expo at the bottom for gas. Bisu has 2 stargates pumping corsair. Only a matter of time before gg. Bisu whips out his trademark dt and rapes gorush. 3-1 Bisu