This Reaper FE gets out exactly one Reaper for scouting while taking a quick expansion to start the economic midgame.
- 10 – Supply Depot
- 12 – Barracks
- 12 – Refinery
- 15 – Orbital Command
- 15 – Reaper
- 17 – @100% Reaper, start Reactor on Barracks
- 17 – @400 Mins, start 2nd Command Center
- 18 – Supply Depot
- 20 – Bunker
- Benchmark: When you start your Bunker (@4:10ish), you should have 1 Reaper and 17 SCVs.
This build has a fragile beginning (opening with a Reaper FE means that you only have 1 Reaper for quite some time), so scouting with this Reaper is absolutely crucial. You CANNOT lose your Reaper. Instead, use it to spot how many Assimilators your opponent has taken, when they expand (or note if they do not get a fast expansion by around the 5 minute mark), and how many early game units they are defending with. You must keep the Reaper active on the map to spot for any early aggression and also to prevent your opponent’s first Stalker or Zealot/Stalker from getting to your base and doing damage.
This build can transition into Bio or Mech play, for you have only committed into a Reaper to scout.
To transition into Mech play, start a Factory with your next 100 gas and go for a Widow Mine Drop or Reactored Hellion production to take map control. Start all your Refineries and go up to 3 Factories and a Reactored Starport while getting your 3rd Command Center to transition into a solid Mech midgame.
Pros and Cons
This build is strong because it gives you the economy of a 1rax FE with much better scouting capabilities due to the fast Reaper.
However, this build is quite vulnerable to early Protoss pokes, especially if you lose your Reaper. Another problem with this build is that with such a low Marine count in the early game, fast Oracles can do a lot of damage if your scouting/turret timing is not perfect.
This build is strongest on larger maps and also maps with lots of cliffs on the main base so that a Reaper can jump up and get lots of scouting information. Also it works well on any maps with a safe natural so that your opponent is more likely to expand instead of try to all-in you.