# Counter-Strike: Source
**Counter-Strike: Source** is a team-based first-person shooter developed and published by [Valve Corporation](https://www.edgepedia.org/valve-corporation), released on 1 November 2004 as the third main entry in the [Counter-Strike](https://www.edgepedia.org/counter-strike) franchise[1](https://store.steampowered.com/app/240/CounterStrike_Source/) • [2](https://counterstrikewiki.com/Counter-Strike%3A_Source). It rebuilt the objective-based terrorist-versus-counter-terrorist gameplay of [Counter-Strike 1](https://www.edgepedia.org/counter-strike-video-game).6 on Valve's new Source engine, adding modern graphics, physics simulation, and ragdoll character deaths while keeping the core game design largely unchanged[2](https://counterstrikewiki.com/Counter-Strike%3A_Source) • [3](https://csdownload.ru/en/articles/cs16-vs-css).
| Key fact | Detail |
|---|---|
| Release | 1 November 2004, developed and published by Valve[1](https://store.steampowered.com/app/240/CounterStrike_Source/) |
| Engine | First game on the Source engine, showcasing HDR lighting, ragdoll physics, Havok physics simulation, and higher-poly weapon models[3](https://csdownload.ru/en/articles/cs16-vs-css) |
| Design intent | Gameplay deliberately kept identical to 1.6; the pitch was "same game, better engine"[3](https://csdownload.ru/en/articles/cs16-vs-css) |
| Hitboxes | Generous hitboxes expanded beyond the character model, unlike the smaller hitboxes later used in CS:GO[4](https://blog.counter-strike.net/2012/03/1838/) |
| Competitive reception | Professional players largely stayed with 1.6 while Valve pushed for Source's popularity[5](https://research-api.cbs.dk/ws/portalfiles/portal/105667820/1659354_155461_Matus_Jakubicka_Fragging_Through_Time_A_Case_Study_on_factors_influencing_the_evolution_of_the_professional_Counter_strike_ecosystem.pdf) |
| Player reception | 96% of 45,319 English Steam reviews positive; Metacritic score 88[1](https://store.steampowered.com/app/240/CounterStrike_Source/) |
| Concurrent players | All-time Steam peak of 60,896 (September 2025); recent 30-day average of about 2,293 players[6](https://steamcharts.com/app/240) |
## Development and release
Counter-Strike began in 1999 as a mod for Half-Life, and Valve bought the rights and released it as a commercial product in 2000[7](https://catalogimages.wiley.com/images/db/pdf/9780470096314.excerpt.pdf). Counter-Strike: Source was built as a technology showcase for Valve's new Source engine, demonstrating HDR lighting, ragdoll physics, [Havok](https://www.edgepedia.org/havok-software) physics simulation, and higher-poly weapon models[3](https://csdownload.ru/en/articles/cs16-vs-css). It debuted on the engine in June 2004, several months before [Half-Life 2](https://www.edgepedia.org/half-life-2) shipped in November of that year[8](https://www.youtube.com/watch?v=pRvJ_WHsJp8).
The release was preceded by a well-known security incident. In 2003, Valve's network was breached and the source code, maps, models, and playable builds of both Half-Life 2 and Counter-Strike: Source were stolen and leaked, delaying Half-Life 2 by 13 months from its planned September 2003 date[9](https://www.pcgamer.com/biggest-gaming-leaks/).
Minh Le, co-creator of the original Counter-Strike, later said Valve offered him a chance to work on Counter-Strike: Source but that the studio "didn't want to change anything - they just wanted to upgrade the graphics"; he left the company amicably afterward[10](https://www.gamesradar.com/games/fps/og-counter-strike-co-creator-has-some-regrets-over-leaving-a-lot-of-the-people-who-i-still-keep-in-touch-with-at-valve-i-kind-of-notice-that-theyre-really-well-off-financially/).
## Technical changes from 1.6
The move from the [GoldSrc engine](https://www.edgepedia.org/goldsrc) to Source changed the game's physics and movement mechanics significantly[2](https://counterstrikewiki.com/Counter-Strike%3A_Source). Character deaths used ragdoll animations instead of static hitbox-driven animations, and the content library included both maps ported from the 1.6 era and new environments designed for the Source engine[2](https://counterstrikewiki.com/Counter-Strike%3A_Source). Grenade behavior changed as well: in 1.6 grenades fly where you throw them, while Source's physics engine produced different trajectories[11](https://gaming.stackexchange.com/questions/76014/what-are-the-differences-between-counter-strike-1-6-and-cssource).
Hitbox size became the most debated change. According to Valve's own CS:GO blog, in Counter-Strike: Source the "generous hitboxes expanded on the character's model," whereas in 1.6 the hitboxes surrounding the characters are generous but the models are smaller, making players harder to hit[4](https://blog.counter-strike.net/2012/03/1838/). Community discussion frequently cites these larger hitboxes and easier recoil as reasons Source felt less demanding than 1.6[12](https://steamcommunity.com/app/240/discussions/0/619568192961692750). Source also added lag compensation, which made playing with high ping less punishing than in 1.6, where high ping is a large disadvantage[13](https://steamcommunity.com/app/240/discussions/0/6278597937786501062/).
The engine's more grounded physics also altered movement. Air strafing, the high air acceleration that gave 1.6 its characteristic "floaty" feel and sharp mid-air directional changes, was rewritten in Source to approximate the GoldSrc air acceleration values[14](https://csdownload.net/cs-legacy-vs-1-6/).
## The competitive split
Counter-Strike: Source, released 14 months after CS 1.6, failed to replace it in the competitive scene[3](https://csdownload.ru/en/articles/cs16-vs-css). A case study of the professional Counter-Strike ecosystem notes that, with the rise of esports, professional players were more keen to stick with the 1.6 version while Valve was trying to push for more Source popularity[5](https://research-api.cbs.dk/ws/portalfiles/portal/105667820/1659354_155461_Matus_Jakubicka_Fragging_Through_Time_A_Case_Study_on_factors_influencing_the_evolution_of_the_professional_Counter_strike_ecosystem.pdf). A Finnish thesis on the franchise similarly records that Source, released in 2004, never got the same hype and competitive atmosphere as Counter-Strike 1.6[15](https://www.theseus.fi/bitstream/handle/10024/783959/Aallo_Mikko.pdf?sequence=2).
The reasons cited combine technical and social factors. Many established players found Source's gunplay and hitboxes less precise and predictable than 1.6's[16](https://counterstrike.de/historie/counter-strike-source/).
## Later updates and community
A 2010 engine update tied to the Orange Box release changed the technical identity of Counter-Strike: Source and affected its modding community[17](https://shapes.inc/fandom/counter-strike-source/deep-dive). The game remains sold on Steam, both alone and in bundles such as Counter-Strike Complete with [Counter-Strike: Condition Zero](https://www.edgepedia.org/counter-strike-condition-zero), and it includes the Source SDK for modding[1](https://store.steampowered.com/app/240/CounterStrike_Source/).
The game retains an active player base more than two decades after release. Steam Charts recorded an all-time peak of 60,896 concurrent players in September 2025, with monthly averages in the tens of thousands through mid-2026 before settling to a recent 30-day average of about 2,293 players[6](https://steamcharts.com/app/240). [PC Gamer](https://www.edgepedia.org/pc-gamer) noted in 2026 that both the original Counter-Strike and Source still have healthy playerbases of their own[18](https://www.pcgamer.com/games/fps/counter-strike-2-might-be-the-biggest-game-on-steam-but-global-offensive-is-breaking-player-count-records-since-it-went-standalone-again/).
## Reception
On Steam the game holds "Overwhelmingly Positive" reviews, with 96% of 45,319 English user reviews positive, and a Metacritic score of 88[1](https://store.steampowered.com/app/240/CounterStrike_Source/). Contemporary reviews described it as a graphical update to 1.6 that moved the game to the Source engine, offering little gameplay difference but new graphics that made it worth the price[19](https://gamefaqs.gamespot.com/pc/922013-counter-strike-source/reviews/116101) • [20](https://gamefaqs.gamespot.com/pc/922013-counter-strike-source/reviews/80565).
## References
1. [Counter-Strike: Source on Steam, Valve](https://store.steampowered.com/app/240/CounterStrike_Source/)
2. [Counter-Strike: Source, CS2 Wiki](https://counterstrikewiki.com/Counter-Strike%3A_Source)
3. [CS 1.6 vs CS: Source - The Split That Never Healed, WarzoneCS](https://csdownload.ru/en/articles/cs16-vs-css)
4. [Hitboxes, Counter-Strike: Global Offensive blog, Valve (20 March 2012)](https://blog.counter-strike.net/2012/03/1838/)
5. [Matus Jakubicka, Fragging Through Time: A Case Study on factors influencing the evolution of the professional Counter Strike ecosystem, Copenhagen Business School thesis](https://research-api.cbs.dk/ws/portalfiles/portal/105667820/1659354_155461_Matus_Jakubicka_Fragging_Through_Time_A_Case_Study_on_factors_influencing_the_evolution_of_the_professional_Counter_strike_ecosystem.pdf)
6. [Counter-Strike: Source, Steam Charts](https://steamcharts.com/app/240)
7. [Book excerpt on Half-Life and Counter-Strike history, Wiley](https://catalogimages.wiley.com/images/db/pdf/9780470096314.excerpt.pdf)
8. [Evolution of Source Engine Games 2004-2020, YouTube](https://www.youtube.com/watch?v=pRvJ_WHsJp8)
9. [The biggest leaks in PC gaming history, PC Gamer](https://www.pcgamer.com/biggest-gaming-leaks/)
10. [OG Counter-Strike co-creator has "some regrets" over leaving, GamesRadar+](https://www.gamesradar.com/games/fps/og-counter-strike-co-creator-has-some-regrets-over-leaving-a-lot-of-the-people-who-i-still-keep-in-touch-with-at-valve-i-kind-of-notice-that-theyre-really-well-off-financially/)
11. [What are the differences between Counter Strike 1.6 and CS:Source?, Arqade](https://gaming.stackexchange.com/questions/76014/what-are-the-differences-between-counter-strike-1-6-and-cssource)
12. [CSS is so bad compared to 1.6, Steam Community discussion](https://steamcommunity.com/app/240/discussions/0/619568192961692750)
13. [Whats the difference between Counter-Strike Source and Counter-Strike Classic?, Steam Community discussion](https://steamcommunity.com/app/240/discussions/0/6278597937786501062/)
14. [CS Legacy vs CS 1.6 - Differences & Current Status, csdownload.net](https://csdownload.net/cs-legacy-vs-1-6/)
15. [Aallo Mikko, thesis on the Counter-Strike skins market, Theseus](https://www.theseus.fi/bitstream/handle/10024/783959/Aallo_Mikko.pdf?sequence=2)
16. [Counter-Strike: Source (2004), counterstrike.de](https://counterstrike.de/historie/counter-strike-source/)
17. [Counter-Strike: Source Deep Dives, Shapes](https://shapes.inc/fandom/counter-strike-source/deep-dive)
18. [Counter-Strike 2 might be the biggest game on Steam, PC Gamer](https://www.pcgamer.com/games/fps/counter-strike-2-might-be-the-biggest-game-on-steam-but-global-offensive-is-breaking-player-count-records-since-it-went-standalone-again/)
19. [Counter-Strike: Source Review, GameFAQs](https://gamefaqs.gamespot.com/pc/922013-counter-strike-source/reviews/116101)
20. [Counter-Strike: Source Review, GameFAQs](https://gamefaqs.gamespot.com/pc/922013-counter-strike-source/reviews/80565)
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*Initially written Sep 17, 2026 · Reviewed: Sep 19, 2026; Oct 21, 2026 · Edited: Sep 19, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license