Stellaris: Megacorp: build and gameplay guide

This build is viable on default settings, medium+ map, Captain difficulty, Ironman.
Captain is imo the best difficulty as AIs are not pathetic like on Ensign and are putting up a decent competition and fights. Below, and it’s you cheating, above, and it’s AI.

This build is all about getting early game advantage. “Beginnings are such delicate times”.

In the early expansion phase grabbing systems and colonizing planets faster is the key objective, thus the Authoritarian ethic for extra influence and Private Prospectors civic for massive colony ship discount. A slight reduction to empire size from lots of planets and systems is also useful.
Adaptive trait combined with immediate access to medical workers from Pharma State civic moves normally yellow planets into green zone.

But grabbing fast is not enough, development must also quicken. There are two hurdles for the early game economy: minerals and pops.
First problem is solved by buying thousands of minerals on market by spending a huge trade value income from executives, clerks and medics boosted by a Xenophile ethic and Thrifty trait.
Second is addressed through medics and the Mechanist origin: adaptive frames robots from the start. Normally robot assembly plant is too expensive to build and maintain on every new colony but not with the trade value income of this build. Materialist ethic is a prerequisite.

Natural Engineers trait is there for getting industrial tech faster, farther boosting economy.

Unruly and Fleeting traits are insignificant in early game and can be gene-modded out later.

Set your capital, science and construction ship on auto.

Key early techs are blue lasers, hydroponic farming and fleet support doctrine.

Go to policies and set vassal policy to negotiated synergy and bombardment to selective because authoritarian does not always mean Stupid Evil. In edicts enable the information quarantine, another good reason for being authoritarian.

Get colonization fever from expansion tradition tree (you should be colonizing guaranteed planets already) then build and crew science ships up to the limit and set them on auto as well. You can exceed the limit by hiring eager scientists. Research anomalies and projects immediately, leave excavations to lvl III-IV.

Redesign your corvettes to PD (all energy weapons) and defence platforms to hangars. Build some corvettes with alloys left from colonization.

Expand your council with agenda first, pharma executive is a nice bonus and other agendas mostly scale with economy. Shuffle your council positions so you get all three ethics represented when factions appear. If you are into conquest, imperialist faction is likely to form as well. The rest can be ignored and suppressed when small enough. Especially those insane Manifesti.

If you find highly developed pre-FTLs sadly you cannot invade them immediately but save 100 influence to annex them when they become spacefaring.

Set smaller planets you colonize to Tech and big ones to Forge. By this time you should also get adaptive policies from Mercantile tree and set it to Consumer Benefits to remove market inflation factor from buying consumer goods.

Important thing is to keep resource incomes and storages close to zero (except minerals, you require more minerals), that is achieved by only building basic resource districts to prevent the global deficit, your main resource is trade value. Buying alloys can quickly get expensive though, thats why you designate forge worlds. Don’t build any agri districts until midgame, you can get by with hydroponic farms on stations and market. Don’t go spamming those commercial zones everywhere too, one per high pop count planet for buffing the trade value is enough.

Building a corporate culture center on every planet will keep the traditions rolling, speaking of which after you encounter a friendly neighbour(s) you will need diplomacy tradition for treaty cost discount and forming a federation. A choice of federation type is trade if you need more unity, or research for guess what.

In your branch offices build private labs first, best value for slot plus helps in out-teching the competition.

First ascension perk should be mastery of nature (you will need it due to your higher than intended pop growth), second whatever like technological ascendancy, third – ascension path depending on your precursor or the flesh is weak by default as it synergizes well with roboticists you have everywhere.

By keeping a fleet of about 40-50 corvettes and a few frigates you are likely to deter any hostile neighbour from attacking early, so you can keep those rivalries until they are invalidated by you becoming superior. If you prefer to attack, ‘always’ get the fleet intel first. It is viable to declare a claim war when the enemy is weaker and haves valuable bordering systems or when you ran out of unclaimed space but generally vassalization or ideology war for integrating into federation is better due to empire size malus.

With all that said and done, you should be safely into midgame, keeping top score just below the fallen empires. If you won’t do something suicidal (comparing fleet strength numbers helps) it is only a matter of time until you win the game, the endgame crisis on default settings is easily contained by awakened fallen empires.