Counter-Strike: Condition Zero was never officially released for Android by Valve or Sierra Entertainment. Any Android version available today is an unofficial port (typically based on the Xash3D engine or a modified Source engine build). This review covers the functionality, installation, and gameplay of those fan-made ports.
None of these are CS:CZ, but they are safe, run natively, and have online multiplayer.
Paste the valve and czero folders into this new xash directory.
The search for is understandable—nostalgia is powerful. But the golden rule of mobile gaming remains: If it is too good to be true (a massive PC game compressed into a single click), it is almost certainly malware. Respect the game, own it legally on PC, and use the emulation tools the community has legitimately built.
Xash3D is a clean-room reimplementation of the GoldSrc engine. It does not contain copyrighted data, only the code to read your legitimate data.
Create a folder named xash on your Android device's internal storage.