Ravenfield

Where it really earns the “forever-installed” status is replayability. Even without mods, the game supports big battles and different ways to approach them. And with its Conquest layer (a world map where you choose territories to take for reinforcements/resources), it has that “just one more territory” pull that quietly eats your evening.

Now add mods, and Ravenfield stops being “a game” and becomes a platform. The Steam page is explicit about the goal: modding support with custom levels, vehicles, and weapons, plus Steam Workshop integration and even a level editor. In practice, the Workshop is a firehose of content—maps, weapons, vehicles, skins, mutators—ranging from grounded military kits to totally unhinged meme warfare. One week you're running a “semi-serious” modern combat setup; the next week you're storming beaches with a loadout that looks like it was assembled by a sleep-deprived prop department. That constant “what if I try this mod combo?” is why Ravenfield never really runs out.

The one big disappointment: no true built-in multiplayer. Ravenfield is marketed and designed as single-player first, and you feel that. Yes, the community has stepped in—there's RavenM, a free multiplayer mod/plugin (very WIP by its own admission), and there's also the separate community project “Ravenfield: Multiplayer Mod” (RFMP) on Steam. But community multiplayer is never quite the same as “official, seamless, supported forever,” and it's a shame because this sandbox would be absolutely lethal with polished native co-op/versus.

Still: Ravenfield's magic is that it doesn't need multiplayer to be endlessly entertaining. The AI-battle premise, the scale, the vehicles, the silly physics, and the mod ecosystem combine into a game that constantly creates new “how did this happen?” moments—often five seconds after you confidently said, “I've got this.”