Gordon Freeman's journey through City 17 and beyond follows a carefully crafted progression that rewards smart play and punishes careless mistakes. This Half-Life 2 walkthrough breaks down the optimal path through each chapter, highlighting critical decisions and techniques that separate efficient players from those who struggle against the Combine.
Whether you're tackling physics puzzles or preparing for the final assault on the Citadel, understanding the game's rhythm makes all the difference. Check out our beginners guide for essential mechanics before diving into this progression overview.
Table of Contents
- Early Game Foundation (Chapters 1-3)
- Combat Fundamentals and Physics Introduction
- Mid-Game Power Spike (Chapters 4-7)
- Vehicle Mastery and Resource Management
- Late Game Challenges (Chapters 8-11)
- Endgame Strategy and Final Assault
- Achievement Optimization
Early Game Foundation (Chapters 1-3) {#early-game-foundation}
The opening chapters establish your core skillset without overwhelming you with complex mechanics. Point Insertion serves as your introduction to Source engine physics, but don't get distracted by every interactive object. Focus on learning the crowbar's attack patterns and basic movement mechanics.
"A Red Letter Day" introduces critical NPCs and story elements. Pay attention to Barney's dialogue about your suit - you'll need this information later. The most common mistake here is rushing through conversations. Take time to absorb the world-building, as it directly impacts your understanding of later plot points.
During "Route Kanal," prioritize learning the flashlight's battery management system. The flashlight drains in 60 seconds but recharges in 30. Always turn it off when you don't need it, especially in areas with ambient lighting. This habit prevents frustrating situations in darker chapters ahead.
The chapter's HL2 physics puzzles start simple but teach essential concepts. When stacking cinder blocks to reach higher areas, place heavier objects at the bottom for stability. This technique becomes crucial in later chapters where unstable structures can trap you or block essential paths.
Combat Fundamentals and Physics Introduction {#combat-fundamentals}
"Water Hazard" transforms the game's pace completely. The airboat controls feel loose initially, but mastering the turn radius and acceleration patterns saves significant time. Hold down the accelerator constantly - the airboat has excellent fuel efficiency and stopping frequently makes you an easy target.
Civil Protection officers in this chapter have 30 health points each. The crowbar deals 25 damage per hit, requiring two strikes for most enemies. However, headshots with thrown objects deal instant kills. Practice your physics-based attacks here because ammunition becomes scarce in later chapters.
Barnacles pose the first real environmental threat. They grab you at a range of 4 feet and deal 10 damage per second. If caught, fire any weapon to break free instantly rather than waiting for the damage-over-time to kill you. This mechanic appears throughout the game, so develop quick reflexes now.
The chapter's most challenging section involves navigating the dam machinery. The spinning blades operate on a 12-second cycle. Count "one Mississippi, two Mississippi" up to twelve, then boost through during the 4-second safe window.
Mid-Game Power Spike (Chapters 4-7) {#mid-game-power-spike}
"Black Mesa East" provides your first major equipment upgrade with the Gravity Gun. This tool transforms how you approach every subsequent encounter. Practice the primary fire (punt) and secondary fire (pull/hold) mechanics on harmless objects before entering combat situations.
The Gravity Gun's pull function works on objects up to 15 feet away, but accuracy decreases with distance. For precision work, move closer to your target. The weapon can hold objects indefinitely without draining energy, making it perfect for carrying supplies through long stretches.
"We Don't Go to Ravenholm" tests every skill you've learned. Father Grigori provides unlimited shotgun ammunition, but relying entirely on guns wastes opportunities to practice physics combat. The chapter contains 47 saw blades scattered throughout - each one represents a potential one-hit kill against most enemies.
Headcrab Zombies have 50 health points. Regular headcrabs have 10. Fast headcrabs (introduced here) have 10 health but move 40% faster. Poison headcrabs have 35 health and their attacks reduce you to 1 HP rather than killing you outright. Learn these distinctions because different tactics work better against each variant.
The spinning blade trap in Ravenholm's playground area kills any enemy instantly. Lure zombies into the center, then activate the mechanism with the red button. This technique eliminates entire groups without spending ammunition.
Vehicle Mastery and Resource Management {#vehicle-mastery}
"Highway 17" and "Sandtraps" emphasize vehicle combat and resource conservation. The Combine uses two types of hunters during these chapters: gunships (aerial) and APCs (ground-based). Each requires different strategies.
Gunships have 800 health points and regenerate 50% of damage taken over 10 seconds if not attacked continuously. Always maintain pressure with the rocket launcher. The vehicle-mounted rocket launcher has unlimited ammunition but requires 3-second reload intervals between shots.
For efficient gunship takedowns, fire rockets in groups of three, then take cover during their missile barrage phase. Each gunship fires 6-8 missiles in sequence, followed by a 5-second vulnerability window. Time your attacks during these windows for maximum effectiveness.
Antlions in the sand chapters follow specific behavioral patterns. They detect vibrations through sand but cannot sense you on hard surfaces like concrete, metal, or wood. Plan your routes between safe zones, and never sprint across sand unless absolutely necessary. Walking generates 50% less vibration than running.
The bugbait mechanic introduced here revolutionizes combat encounters. Each piece of bugbait controls up to 8 antlions simultaneously. Target enemies by throwing the bait near them - antlions prioritize the most recent bait location. This crowd control technique trivializes several difficult combat encounters in later chapters.
Late Game Challenges (Chapters 8-11) {#late-game-challenges}
"Nova Prospekt" combines every mechanic you've mastered into intense combat scenarios. The prison features three difficulty spikes that catch unprepared players off-guard. Stock up on health and ammunition before entering each major battle area.
Combine soldiers have varying health totals: Civil Protection (30 HP), Metro Cops (40 HP), Combine Soldiers (50 HP), and Elite Soldiers (70 HP). Shotgun blasts deal 60 damage at close range but drop to 20 damage beyond 15 feet. Adjust your tactics accordingly.
The prison's turret defense sequences require specific positioning. Place turrets in corners where they cannot be flanked, and always maintain at least two active turrets per chokepoint. Turrets have 100 health and unlimited ammunition but overheat after firing continuously for 15 seconds.
"Entanglement" introduces the Super Gravity Gun, which can manipulate Combine soldiers directly. This weapon launches enemies with enough force to kill other soldiers on impact. A single thrown soldier can eliminate entire groups, making previously impossible encounters manageable.
Practice the Super Gravity Gun's timing during the early sections. Primary fire launches immediately, while secondary fire requires a 2-second charge but deals 300% more damage. Use charged shots against heavily armored enemies and quick shots for crowd control.
Endgame Strategy and Final Assault {#endgame-strategy}
"Dark Energy" and "Our Benefactors" culminate in the Citadel assault. The final elevator sequence requires precise timing and positioning. Striders have 400 health points and take reduced damage from conventional weapons. Focus on using the Super Gravity Gun to launch Combine energy cores directly at their weak points.
The reactor core sequence follows a specific pattern. Each core must be charged for exactly 10 seconds before insertion. Charging for less time results in failure; charging longer causes the core to explode. Count carefully and watch for the blue energy glow that indicates full charge.
Dr. Breen's final monologue can be interrupted by shooting the monitor screens around his platform. This skips approximately 90 seconds of dialogue and moves directly to the escape sequence. However, patient players who listen to the complete speech unlock additional context for the series' overarching plot.
Achievement Optimization {#achievement-optimization}
A complete Half-Life 2 achievement guide requires multiple playthroughs, but several achievements can be earned during your first run with proper planning. "Lambda Locator" requires finding all Lambda caches - there are 45 total, with specific caches in each chapter providing essential supplies for later encounters.
"Zombie Chopper" demands killing 1,000 zombies with the propeller blade in Ravenholm. This seems excessive, but the spinning playground trap counts toward this total. Repeatedly luring zombies into the mechanism can complete this achievement in a single chapter.
Half-Life 2 mods like "Cinematic Mod" and "MMod" add new achievement categories and gameplay mechanics. However, these modifications can interfere with Steam achievement tracking, so complete your achievement hunting in the vanilla game first.
The "Vortigaunt Hunter" achievement requires killing specific Vortigaunts who appear as allies in certain chapters. This achievement is missable and requires careful attention to dialogue cues that identify hostile versus friendly Vortigaunts.
Start your second playthrough immediately after finishing the main campaign. The game's pacing becomes much clearer once you understand the overall story structure, and advanced techniques like speedrun strategies become more accessible with experience. Focus on mastering one chapter at a time rather than rushing through the entire campaign again.