For legitimate free PC games, you can check weekly giveaways on the Epic Games Store or browse the "Free to Play" sections on Steam and GOG.
The official version of Zcrew can be purchased and downloaded on Steam. This is the only way to ensure you have the full, updated version with online multiplayer support and no security risks.
Developers occasionally release free demos or "prologue" versions on Steam that allow you to play a portion of the game for free before buying.