Influential FPS Games #17: Half-Life 2

Updated: Feb 24

A short while back, we investigated the impact made by Halo: Combat Evolved, and in the last article its slightly less imaginatively named sequel, Halo 2. Most FPS games that came out after Halo implemented its innovations, such as; a two-gun limit, regenerating shields and dedicated grenade toss and melee attack buttons. With one major exception - Half-Life 2 - the topic of this article. Let’s dive in.

Lip-Syncing, Body Language and Facial Expressions

In many ways, Valve’s Half-Life 2 (HL2) was a riddle wrapped in a mystery inside an enigma. On the one hand, its technology was ahead of its time and dropped jaws amongst gamers and critics alike, as you can see and hear in the video below. (Apologies for the blurry video. I suspect this was taken on an attendee’s phone, and the video cameras in the phones of 2003 were not up to much.)

Half-Life 2 Tech Demo - E3 2003

NB - If you turn up the volume you may be able to hear the presentation.

Video by muffinhunter

In particular, the body and facial animations were far in advance of anything seen in a game up to that point. This added a new set of tools for storytellers, who could now convincingly convey mood, intention, exertion, pain, fear, anger, etc. through expressions and body language. This would go on to become an increasingly important part of games. The Last of Us made particularly good use of this to tell its gut-wrenching story.

Facial expressions and body language have even been used as a core mechanic in some games, most notably in the investigative LA Noire. In this, the player must read suspect’s and witnesses’ body language and facial expressions to determine if they are lying, withholding information, afraid of repercussions, etc.

Half-life 2’s lip-synching was revolutionary. Instead of animators having to attempt to match the character's mouth movement to the sounds, the sounds themselves animated the lips. This is how the G-Man from the video above was able to lip-sync to foreign languages so effectively. You can learn more about how this process works here.


Another of Half-life 2’s great innovations was its remarkable in-game physics. Physics have been implemented in previous FPS games of course. In Halo, for example, we saw both the Covenant and the UNSC NPCs being sent flying from grenade explosions and then rag-dolling over the scenery. However, Half-Life 2 incorporated the Havok physics engine, which took in-game physics to a new level. This was incorporated into the game’s core gameplay.

The term ‘physics puzzle’ has become commonplace, but it was very rarely - if ever - heard before HL2. Indeed, it may have coined the term. Boxes could be moved to create steps, breezeblocks placed on planks to act as counterweights, and corrugated metal sheets used as stepping stones for the world’s most dangerous game of ‘the floor is lava’.

Half-Life 2 (100%) Walkthrough (Chapter 8: Sandtraps)

If even the tip of your toe touches the tiniest bit of sand you don’t get the achievement. You also get swarmed by Antlions. Standing on a flimsy plank on top of the sand is ok, because, err, ‘reasons’?

Video by BigMacDavis

Or you could try the method below…

From the hilarious webcomic ‘Concerned’

From the hilarious webcomic Concerned

Central to manipulating the environment was the Gravity Gun. Part tool, part weapon, the Gravity Gun can pull things towards the player, suspend them in mid-air and forcefully propel them towards targets. This becomes vital in the ‘We Don’t Go To Ravenholm’ chapter, where zombies are plentiful but ammo is scarce. This forces the player to get creative and use objects in the environment as weapons.

Physics manipulation such as this started to appear in other franchises, for example, the Temporal Uplink in Time Splitters: Future Perfect and The Force powers in Star Wars: Force Unleashed. It may also have been the inspiration for Singularity’s Time Manipulation Device (TMD).

Half-Life 2: Full Walkthrough

Half-Life meets Resident Evil: We Don’t Go To Ravenholm’

Video by Bolloxed

One Foot in the Future, One in the Past

Although technologically Half-Life 2 was 'next-gen', aspects of its gameplay felt distinctly ‘old skool’. For example, it used the same non-regenerating health mechanic as the first Half-Life. What’s more, your avatar could carry the entire in-game arsenal at the same time. Aim Down Sights (ADS) only worked with the game’s dedicated sniper-weapon - the crossbow. Furthermore, there were no dedicated grenade toss or melee attack buttons. These are likely due to HL2’s five-year development cycle - it would have started development before Halo was released.

This resulted in a game that was both anachronistic and a glimpse at the future of gaming at the same time. Some said it felt out of time, whilst others felt this gave it a unique charm.

If Half-Life was a textbook example of how to create a sense of ‘place’, then HL2 was a textbook example of ‘pace’. Each chapter felt unique, and many were divided into separate sections.

Some areas saw your avatar having to run or drive for their lives as they were unarmed and attempting to escape enemy territory, whilst others saw the avatar go on the offensive. These intense sections were interspersed with areas that were either safe or required a slow, methodical approach. This created a superb ‘ebb and flow’ pacing which prevented the game from becoming boring or overwhelming.

Impact of The Source Engine

HL2’s impressive features are all thanks to the engine it ran on, the Source Engine. Valve allowed developers to use the engine for free, so long as the game or mod was free. Licensing fees only applied if the game was being sold retail.

This made it an extremely attractive engine for modders and indie developers. Some of these mods, such as the sandbox Garry’s Mod and the fourth-wall-breaking The Stanley Parable went on to become retail releases. Some modders were hired by Valve to work on commercial projects, such as Half-Life Alyx.

Valve would go on to use the Source engine for all their first-person games, such as Half-Life Episodes One and Two, Team Fortress 2, Left for Dead One and Two and the two Portal games.

It was also licensed by third parties to create several superb titles such as Vampire: The Masquerade - Bloodlines, Zeno Clash and Titanfall 2.

Source FilmMaker SFM

On the back of the Source Engine came Source Filmmaker (SFM). This allowed players and budding animated filmmakers to create films using the source engine and its assets. In the right hands, it could create shorts that would give Pixar a run for their money