2 Gate Rush (vs. Zerg)
From Liquipedia Starcraft 2 Wiki
Two Gateways are built before the Cybernetics Core, from which Chronoboosted Zealots are produced for early aggression. This is meant to force Zerg to produce early Zerglings, and possibly kill Drones, Queens, or an expansion Hatchery. Gateways can be placed outside your expansion to wall off your expansion on some maps.
This build is meant to punish early expansions, and Zergs who have not teched to Roaches. The build will force your opponent to get Roaches and Roach tech. Your economy is slightly hurt by this build, and you will be behind in tech, so you must deal significant damage or win outright with this build. There are many variations of this build, which revolve around the Gateways are built.
It is also used heavily in team games as a means of applying early pressure or punishing opponents who try to tech or expand too fast.
 Basic Build Order
 Attack Timing
The earlier the Zerg places their Spawning Pool, the more Zealots you need before you attack. A rule of thumb (which is inaccurate and you should test and change to see what works/what fits your playstyle) would be:
- Hatch first- 3 Zealots+Probe
- 14Pool 16Hatch- 5 Zealots+Probe
- 10/12/14 Pool no hatch- 5-7 Zealots
Scouting on 12 is for 4 player maps for the enemy's spawn position. On 2 player maps, you can scout on 14, or not scout at all. If you do not scout, Pylon earlier and begin Probe production at 20/22.
Variations are dependent on when you get your Gateways. Tester uses 13/15, Day9 does 10/11. The 12/14 mentioned in this article is a strategy between the two, providing for a mid-range economy, but not drastically sacrificing attack units. It seems like you cut Probes for quite a long time, but you only really cut 3-4, which is much better than waiting for the next Pylon for your Zealots. Midgame begins when the Zerg techs to Roaches or Lair.
 Midgame Transitions
There are 3 routes to take after this rush finishes, all of which depend on how much damage you've done.
If you did a lot of damage, and can end the game, pump more Zealots. This route is quite all-in, and should only be done if you're 90% sure that you can end the game or cripple the opponent.
This is the path you will take in a majority of your 2gate rushes. If you've killed enough units that the Zerg is behind, then place a Nexus, Forge, and 1-2 Photon Cannons. Be careful using this route, as many Zergs will all-in you if they feel extremely behind. Cutting probes to get faster Photon Cannons is an appropriate response.
If you have done little/no damage, then quickly build an Assimilator, tech, and continue the game normally. However, teching is not always a route when you're far behind; Stargate tech is extremely strong if the Zerg over-commits to defense. Void Rays hard counter a Zergling/Roach army. It should be noted that your Void Rays will be extremely late, so it is very difficult to pull off, especially since the Zerg will likely have multiple Queens out.
 Pro features
- Short rush distances (Steppes of War)
- Narrow chokes to natural expansion (Blistering Sands)
- Long distances between main and natural (Kulas Ravine)
 Con features
- Long rush distances (Desert Oasis)
- Wide entrances to natural (Desert Oasis)
- Short air travel distances (Desert Oasis)