Hello, strategists!
Some of you are new, some of you are old Lambda Wars players. Today I will provide you a full guide to units and buildings in the game and talk about the races.
Let's start with the basics.
"Lambda Wars is a free multiplayer Source Engine modification based on Alien Swarm engine and set in the Half-Life 2 universe that brings the war between mankind and their brutal Combine overlords to a traditional real-time strategy (RTS) setting. Lead the uprising as a commander of the Resistance or crush the rebellion as an overlord of the Combine, with both factions featuring a full host of units, abilities, buildings, research and defenses. Lambda Wars features full-fledged RTS gameplay and a robust RTS interface and is focused on multiplayer but strategic AI opponents and dedicated singleplayer missions are also included."
There are two playable races: Combine and Rebels.
Let's start with Rebels.
Rebels:
Rebels are humans who fight against the Combine. Their main strength is amounts of units they can produce and the frequency of building structures.
If played properly (captured good amounts of flags, etc), they can have up to 5 regular rebel units in the first few minutes.
Scrapyard

Requisition: 30
The main building. This is where scouts and engineers are created. It is also a collection point for gathering scrap. Its a building that allows you the flexibility to build multiple outposts in the map, if you wish to do that. Adds +3 to the pop cap. Rebels start with 3 population.
Units:
Scout

Requisition: 10
Health: 50
Energy: 35
An agile unit that can go invisible and scout an area, like an enemy's base. He isn't fit as an army force, however.
Engineer

Requisition: 20
Health: 90
Your little genious who knows how to do pretty much everything. He builds structures, defences and collects scrap. Pretty much, the most important unit. He's rather fast and that allows him to build multiple bases in a map which is rather useful.
Billet
Requisition: 20
A small house-like structure, that increases the pop cap by +9.
Barracks

Requisition: 60
Requires Scrapyard
Your army generator. This is where your main army forces are produced.
Units:
Partisan

Health: 80
An angry human holding a molotov and a stink bomb in his hands. Molotov leaves a spot on ground that burns anyone or anything touching it, while stink bomb slows any unit that hits its radius.
Rebel, Rebel SG, Rebel AR2



Requisition: 30
Requisition (SG): 35, Scrap 5
Requisition (AR2): 40, Scrap 10
Health: 160
Rebel, who initially holds an SMG and can be upgraded to hold a Shotgun or AR2. Also if frag grenade is unlocked, can throw one for 10 requisition. SG runs faster than regular rebel, while AR2 is slower.
Medic

Requisition: 15, Scrap: 10
Health: 160
Energy: 100
A unit that heals any injured units nearby. Can't heal mechanical units. Allows upgrades for energy regeneration, energy capacity and heal efficiency.
Veteran

Requisition: 50, Scrap: 20
Health: 170
A unit with a wider view distance. Works as a sniper for backing up allied units. Can throw smoke grenades and shoot explosive bolts. Has to position before being able to shoot.
Munition's Depot
Requisition: 40, Scrap: 30
A structure for researching things like AR2, SG, Grenades and other. Instantly unlocks some units and structures for construction.
Triage Center
Requisition: 40, Scrap: 20
A structure that unlocks Medic unit and some structures, like the Radio Tower. Can be used to upgrade Medic abilities.
Special Operations
Requisition: 60, Scrap: 40
Requires a Munition's Depot.
In this structure you can create high-end units, such as RPG, Saboteur, Flamer.
Units:
RPG
Requisition: 40, Scrap: 50
Health: 240
A heavy, but slow unit who is capable of dealing large amounts of damage to mechanical units and structures, yet dealing low amounts to infantary units.
Saboteur
Requisition: 20, Scrap: 20
Health: 60, Energy: 100
A light but sneaky unit that can infiltrate an enemy base, capture its buildings and mech, place bombs and get out. A very useful unit when it comes to strategic approach.
Flamer
Requisition: 40, Scrap: 30
Health: 275
A fast, heavy unit, equipped with a flamethrower leaving a strong smell of nepalm behind. Enemies become crispy!
Rebel HQ
Requisition: 70, Scrap: 40
Requires a Triage Center
The Rebel's main building. At the moment it doesn't wield any useful purpose, apart from creating Dog and Vortigaunts.
Units:
Vortigaunt
Requisition: 40, Scrap: 40
Health: 250
Energy: 200
A species that has come from Xen, that once used to be an enemy to the Human race. Now is fighting alongside humans against the Combine. A caster, a supportive unit that can summon suicidal antlions and use their inner energy to unleash attacks with electricity.
DOG
Requisition: 90, Scrap: 90
Health: 850
Energy: 100
A strong, tanky robot capable of smashing and stunning enemies in a small area. Very fast and can jump, allowing him to avoid heavy barricaded & turret defenses. Can stun Striders.
Defense structures:
Barricades, Manned Turrets:
Barricade - a small improvized barricade made of junk. Health: 400, allows up to 3 cover points.
Manned Turret - a barricade with a manned turret attached to it.
Radio Tower
Requisition: 50
Health: 600, Energy: 100
Requires Triage Center
A large tower that reveals invisible units and provides temporary visibility in an area (35 energy). Can be combined with the teleporter.
Aid Station
Requisition: 60
Requires Triage Center
A small bunker-like structure that heals units inside of it and allows all the units to shoot from inside of it.
Teleporter
Scrap: 60
Requires Munition's Depot
A device that allows global teleportation of units to a visible spot in the map. Can allow the teleportation of ~15 units. Teleportation costs requisition.
Barrel Trap Tower
Requisition: 30, Scrap: 30
Requires Barracks
A tower that launches explosive barrels in a large distance. The barrels can hurt allies.
Combine:
Combine rely a lot on energy reactors that you have to build before building your production structures. Their main resource is Power and they solely rely on it. Combine are normally weak in the beginning but are exceptionally strong in the late-game. Unlike Rebels, they can't build multiple bases as efficiently, as their workers, Stalkers, are fairly slow and take some time to get to one place or the other. It is best for a more experienced player to play Combine as they know the right approach to building their base and gathering resources. Combine in a good player's hands can become easilly stronger than Rebels, as the variation of their units allow them to secure areas and destroy everything in one go.
Combine HQ

Requisition: 300
The Combine Headquarters, the main and most important building on the Combine side. It spawns Stalkers, loyal citizens and is used to increase population. The initial population for Combine is 9.
Abilities:
Population upgrade - Requisition: [50 req][100 req][200 req][300 req], Population: 20, 40, 70, 100
Units:
Loyal Citizen
Requisition: 4
A loyal citizen. Does everything for food. His only real task is to either capture points, scout an area or man turrets. Has very low health and deals very low damage.
Stalker
Requisition: 20
Health: 120
Your builder. Extremely slow, deals low damage, attacks with laser. His slow movement speed won't allow you to move everywhere efficiently, yet two of them can handle a single rebel, kills a scout very easy.
Power Generator
Requisition: 20
Energy per second: 0.15 energy per 3 secs.
Provides power to nearby structures. Most of the Combine structures require power provided by Power Generators, otherwise they wont be constructed or won't operate. The only exceptions are: Energy Cells, Headquarters, Power Generators (and Scrap power generators) and barricades.
Scrap Power Generator
Requisition: 50
Energy per second: 1.25 per 1 sec.
Has to be placed on Scrap Points!
Generates power, doesn't provide power to structures. Can only be placed on free scrap points.
Energy Cell
Requisition: 20
Energy capacity: 50
Collects energy provided by power generators. Doesn't have to be in the area of power generators to collect power. Each energy cell provides 50 energy capacity.
Garrison
Requisition: 60
A structure for creation of infantary units. Requires power to operate.
Units:
Riot Metrocop
Requisition: 20
Health: 225
A fast unit equipped with a shield and a stunstick. Can raise the shield to recieve less damage for the cost of slower movement speed, form a wall with multiple units and provide cover position for ranged units. His attacks with stunstick have a chance to stun the enemy. Can also spawn a manhack and a floor turret (require armory + turret unlock).
This unit is often ignored, players often rush combine soldiers instead.
Metrocop
Requisition: 25
Health: 160
Equipped with an SMG, the metrocop unit has light armor. Can make manhacks and place a floor turret.
Combine Soldier (SMG, AR2, SG)
Requisition: 40, 45, 50 Power: 0, 5, 10
Health: 220
The main infantary unit of Combine. Comes in 3 variants: SMG (standard), SG, AR2. Can toss grenades.
Armory
Requisition: 40, Power: 30
Your research center. Used for unlocking SG, AR2 units, unlocking Strider upgrade, grenades for soldiers and floor turret for metrocops. When constructed, automatically unlocks Special Ops, Headcrab Cannister Launcher and Annihilation Mortar. Requires power to operate.
Mech Factory
Requisition: 35, Power: 10
Used to create mech units, such as manhacks, scanners and rollermines. Requires power to operate.
Units:
Scanner
Requisition: 5, Power: 5
Health: 50
Your best scouting unit. Gives vision in a very large area, can also blind enemies to reduce their radius of vision. Very fast speed.
Manhack
Requisition: 10
Health: 30
A fast unit that is good for slicing your infantary enemies. Works well as a distraction.
Rollermine
Requisition: 10, Power: 15
Health: 100
Rollermines are generally tanky and are used as a distraction or for stunning enemy units. They are physical AI, meaning they move like a physics object.
Special Ops
Requisition: 60, Power: 30
In this structure you create Combine Elites and Combine Snipers. Requires power to operate.
Units:
Combine Elite
Requisition: 60, Power: 20
Health: 300
A tanky and strong unit with heavy armor that can use AR2 or SG (switches between them). Can shoot a Combine ball (a.k.a. "Energy Sphere").
Combine Sniper
Requisition: 50, Power: 35
Health: 160, Energy: 75
A ranged unit who is capable of dealing high amount of damage. Can go invisible. Requires to be in steady position to shoot. Can also shoot from cover points.
Synth Factory
Requisition: 70, Power: 40
Requires a Mech Factory.
Is used to create Synth units: Claw scanners, Hunters and Striders. Has to be powered.
Units:
Hunter
Requisition: 50, Power: 50
Health: 300
An agile unit capable of dealing high amounts of damage. Can jump and charge. While charging hunter can instantly kill various units. Has low resistance to explosions.
Strider
Requisition: 90, Power: 90
Health: 1700
Energy: 75 (Upgrade: 150)
Combine's strongest unit, capable of taking down multiple units with dark energy cannon. Can crouch for faster movement.
Claw Scanner
Requisition: 20, Power: 30
Health: 55
Drops mines that activate when an enemy unit passes by. Mines can also be manually exploded.
Defense structures:
Barricades, Manned turrets.
Annihilation Mortar
Requisition: 150
Requires Armory. Has to be powered.
A defense structure that uses Power to shoot powerful dark energy beams, destroys enemy units in a specific radius. Has a second outter radius that deals less damage. One shot costs 50 power.
Works in short to average radius (2048 units). Requires vision to be used.
Headcrab Cannister Launcher
Requisition: 40, Power: 50
Requires Armory. Has to be powered.
Structure that launches headcrab cannisters in a large radius. Requires vision to be used. Can launch Normal headcrabs, Fast headcrabs and Poison headcrabs.
Regeneration Post
Requisition: 50
Requires Special Ops. Does not require power.
Healing station. Heals units in a short radius.
Combine Power Shield (OVERRUN ONLY)
Requisition: 3
Requires Tier: 2
A shield generator that blocks waves of units. Pushes any enemy unit back.
This is it. Thank you for reading!