3 Roach Rush Speedling all-in (vs. Protoss)
From Liquipedia Starcraft 2 Wiki
The Build uses fast Roaches in order to break the Protoss Wall-in and winning the game by sending in a massive amount of Speedlings.
The aim of the Build is to win the game by sending three early Roaches nullifying the effect of the Protoss Wall-in and swarming in with Speedlings to end the game or at least causing a high economic loss for the Protoss.
 Basic Build Order
Kill scouting Probe with the first available pair of Zerglings, try to hide your Roach Warren as you do not want your opponent to know that you're playing an all-in. The Timing is the key: It is important that your gas comes right after your pool, so you are able to produce three Roaches at once.
You should have exactly 100 Minerals and 100 Gas when you research Metabolic Boost.
You do not want to scout your opponent, just check out for proxy Gateways.
Send your first Overlord to the opponents Ramp(Overlord sight is 9 Range, so you should be able to have vision on the highground without getting the Overlord shot down). When you are at the ramp, you can eventually snipe one Sentry, if not just try to snipe the Zealot in order to break the wall-in and make space for your Speedlings. Kill the left over Units with your Speedlings and then move on to the probeline. If the Cybernetics Core or a Gateway is powered by one Pylon it is a good idea to take the Pylon down and then attacking the Protoss economy.
This build is an all-in and, unless you do damage, you will be far behind. If you must transition out of it, try to expand and pump drones. Be alert for an opportunity to backstab/counterattack when your opponent moves out to buy you additional time.
This is an all-in, so if you haven't done enough damage to the Protoss economy he should be ahead in terms of Harvester-Count. Try to Expand and pump drones, than transition into a normal Roach-Hydra-Corruptor Composition.
Scout the timing. scout for Roach Warren just after pool, keep probe scouting Zerg base just until lings are coming out.
Make a second Gateway to complete your wall. The Wall should be made out of 2 Gateways and a Cybernetics Core.
Use your forcefield to delay the attack while getting some more Stalkers out.
 Pro features
Maps with wide ramps, such as Scrap Station.
 Con features
Maps with long rush distances(e.g. Lost Temple in far positions)