Any site claiming to offer a "free full version" of Mavericks: Proving Grounds is likely a scam or contains malware, as the game servers required for play were never completed and do not exist.
The game was the talk of E3 2018, but the ambition proved too heavy for its foundation. In late 2019, Automaton Games faced "insufficient funding." The project was shuttered mid-development, leaving behind only cinematic trailers and a handful of tech demos.
The game's developer, Automaton Games, entered administration (bankruptcy) in 2019, leading to the immediate cancellation of the project.
The game you are looking for, , was an ambitious 1,000-player battle royale developed by Automaton. However, it is no longer available for download or play. Current Status