ReGameDLL_CS: a rebuilt Counter-Strike 1.6 server library

Rebuilt from the debug symbols in the Linux build

ReGameDLL_CS is a server side GameDLL for Counter-Strike 1.6 and Counter-Strike Condition Zero, and the README is precise about where it comes from. It is the result of reverse engineering the original library mod HLDS, build 6153beta, using the DWARF debug information embedded into the Linux version of HLDS, cs.so.

That last detail is the heart of the project. The Linux build shipped with debug symbols, and those symbols describe the structure of the original library closely enough to rebuild it. What you get is therefore not a wrapper and not a patch, it is a reimplementation of the same binary, with the same entry points and the same exported API, rebuilt from a machine readable description of the original rather than from a disassembly guess.

The stated goal is narrow and sensible: to provide a more stable version of Counter-Strike than the official one, with an extended API for mods and plugins. The extended API is the reason a server operator would look at this at all, since the original library exposes a fixed surface that plugins are written against, and a rebuilt one can add to it.

The repository layout matches the engineering. There is a regamedll directory with the implementation, an msvc directory for the Visual Studio project, a dep directory for dependencies, a dist directory for packaged output, a CMakeLists.txt for the Unix build, a build.sh, a version_script.lds for the linker, and a CHANGELOG.md. Both a Make style build through CMake and a Windows project are provided, which matches the fact that the original library ships as mp.dll on Windows and cs.so on Linux.

Replacing the binary is the whole installation

The installation is short because the compatibility claim is strong. ReGameDLL_CS is fully compatible with the official mod CS 1.6 and CZero by Valve, and all you have to do is download the binaries and replace the original mp.dll or cs.so.

There are two download sources listed. Release builds are on the project releases page, and dev builds come from the GitHub Actions build workflow, which is the same split you would expect, and the dev builds are the ones to avoid on a live server because they are built from whatever is on the branch at that moment.

There is a second variant to know about. ReGameDLL_CS also has a beta version with the latest changes from the official version of Counter-Strike, and you get it by entering the `-beta` option at the command line of HLDS.

That gives you a staging path that is unusually easy to use. Run your normal server with the stock library, swap in the release build and check the behaviour, then add the `-beta` option to get the newer game rules on the same server without changing anything else.

The practical checklist before you swap a production server is short. Confirm your server runs the 6153beta build family that the reimplementation targets, keep the original library file somewhere, because replacing it is the only irreversible step, and read the CHANGELOG, since the new configuration variables change round and money rules by default in some cases.

The compatibility catch: binary analysis plugins stop working

The README carries a warning that deserves more attention than the other notes, because it is the one that decides whether the swap is safe for you.

ReGameDLL_CS is not binary compatible with the original hlds, since it is compiled with compilers other than the ones used for the original mod CS. The consequence stated is that plugins which do binary code analysis, Orpheu for example, probably will not work with ReGameDLL_CS.

This is a direct consequence of the reverse engineering method. The original library was compiled with a particular compiler, at a particular optimisation level, with a particular set of layouts, and Orpheu style plugins work by reading the running process at those addresses. A reimplementation that provides the same API from a different compilation has different internal offsets, so a plugin that reaches into the binary finds nothing where it expects to find something.

The distinction to hold on to is between API level plugins and binary level plugins. A plugin that calls the exported functions is fine, because the API is reproduced. A plugin that patches or reads internal structures is not, and the project says so plainly rather than burying it.

For an operator, the check is concrete. Look at the plugin list of your server and identify which of them are API level and which are binary level, and accept that the second category will need replacing or abandoning. The README does not list which plugins fall into which group, so that determination is on you and on the plugin authors.

New server commands for round and admin control

One of the concrete reasons to run this library is the set of commands it adds on top of the original, and they are documented in a table in the README.

The first is a version command. The game version command shows the GameDLL build version, the date, and a URL, which is the quickest way to confirm which build is actually loaded on a server.

The second is endround, which forces a round to end. Called with the argument `T` it ends the round with a Terrorists win, called with `CT` it ends the round with a Counter-Terrorists win, and called with no arguments it terminates the round as a draw. That is an administrative tool, and in a league or a public server it is the difference between waiting for the round timer and resolving a stuck round immediately.

The third is swapteams, which swaps the two teams and restarts the game, with a one second delay to restart by default. It takes an argument that is either `0` to swap the teams without restarting, or a value greater than 0.001 as the delay in seconds before the round restarts after the swap.

The last group are the cheat style commands, and they are gated. The give command gives a weapon, taking the weapon name as its argument, for example `give weapon_ak47` or `give weapon_usp`, and it requires `sv_cheats 1` to be set. The impulse 255 command gives all weapons and also requires `sv_cheats 1`. The impulse 200 command gives noclip with air acceleration, with the same requirement.

The `sv_cheats 1` requirement is the important line. It means these commands are unusable on a public server with cheats off, which is the correct default, and an operator who wants them has to decide whether to enable cheats for everyone or to expose them through an admin plugin instead.

The configuration variables that change how the game plays

The second half of the value is a set of configuration variables that the original library does not have, and they are documented with defaults, minimums, maximums, and descriptions.

The round flow is the area with the most new control. `mp_round_infinite` is a flags variable for fine grained control, where you choose as many flags as needed: `a` blocks the round time round end check, `b` blocks the needed players round end check, `c` blocks the VIP assassination or success round end check, `d` blocks the prison escape round end check, `e` blocks the bomb round end check, `f` blocks the team extermination round end check, `g` blocks the hostage rescue round end check, and `h`, `i`, `j`, and `k` do the same for the round time checks. The README gives the example that the setting "ae" blocks the round time and bomb round end checks. `mp_roundover` decides what happens when the round timer expires on a map without the scenario of the game, with 0 disabled, 1 a draw, 2 a Terrorists win, and 3 a Counter-Terrorists win. `mp_round_restart_delay` sets the number of seconds to wait before restarting after a win, with a default of 5.

The economy has two of them. `mp_buytime` designates the amount of buy time in minutes, with -1 meaning no time limit and 0 disabling the buy, and the default is 1.5. `mp_maxmoney` sets the maximum money in the game, defaulting to 16000 with a maximum of 999999.

Weapon and item behaviour has the densest cluster. `mp_weapondrop` chooses whether a player drops a weapon on death and which one, with four modes from not dropping at all to dropping all weapons including the secondary. `mp_ammodrop` controls whether ammunition stays on the player, and `mp_nadedrops` controls whether a grenade is dropped on death, with modes to drop the first available grenade or all of them. `mp_hegrenade_penetration` disables grenade damage through walls, and `mp_freeforall` turns the game into a style of play where there are no teams at all.

There is also a round respawn timer in `mp_roundrespawn_time`, an automatic reload on spawn in `mp_auto_reload_weapons`, and a backpack ammunition refill in `mp_refill_bpammo_weapons`, and a team balance switch in `mp_autoteambalance` with three modes: disabled, balancing after the next round, and balancing on the next round.

The point of this list is that it is a behaviour control surface, not a performance one. If you run a public server or a league, these are the dials that let you set the rules to what your community expects rather than to what the 2010 era defaults were.

The licence changed hands in 2025, and the release line is steady

The licence story is unusual enough to be worth reading carefully, and it is documented in the repository itself.

ReGameDLL_CS is licensed under the MIT licence. It was not always so. The README states that it was originally released under GPLv3, and that ReHReGameDLL_CSLDS transitioned to the MIT licence in July 2025 with the agreement of the core contributors, with the details in a LICENSE-TRANSITION.md file at the root of the repository.

That file matters to anyone who forked the project earlier or who relicensed derived work, so it is worth reading before assuming which terms apply to a copy you already hold. The transition is presented as an agreement among contributors rather than a unilateral change, which is the part that makes it credible.

On releases, the numbering is a four part version, and the recent tags are 5.30.0.814 from 2026-05-18, 5.28.0.756 from 2025-03-27, and 5.26.0.668 from 2023-12-31. The last push to the repository was on 2026-09-17 and the project is not archived, so work is continuing even in the gap since the May release.

The project documentation lives at rehlds.dev/docs/regamedll-cs, and the repository itself keeps a CHANGELOG.md, a dist directory for the packaged builds, an msvc directory for the Visual Studio project, and a version script for the linker. The combination of a documented licence transition, a changelog, and a separate documentation site is what separates this from a personal patch, and it is why a server operator can reasonably consider it for a long lived public server.

Editorial conclusion

ReGameDLL_CS fits a server operator running Counter-Strike 1.6 or Condition Zero who wants the round flow, economy, and weapon drop behaviour of the original game to be configurable, who is willing to swap a binary, and who understands the plugin ecosystem it comes from. It does not fit a server that depends on plugins doing binary code analysis, since the binary is not compatible with the original, and it does not fit an operator who cannot accept a reverse engineered replacement of a Valve library. Verify first that the plugins you run do not rely on binary layout, that the release you install matches the Counter-Strike build your server expects, and that the cvar defaults you inherit match the behaviour your players are used to, since several of the new variables change round and money rules.

Frequently asked questions

Official sources

1. License: MIT
2. Project website
3. README
4. rehlds/ReGameDLL_CS on GitHub
5. Releases