Fully cross-platform for the usual suspects on desktop, mobile and web.
If you want to publish on consoles you need to pay someone who ported the engine to the console you want to target (or port the engine yourself). The code can't be open source because of licensing issues.
The vast majority of Unity/Unreal games don't have native Linux builds despite the engines ostensibly having native Linux support. Developers don't see it as worth the QA/support hassle, especially now that they can do nothing and still get Linux customers thanks to Proton.
Valve are even pushing developers towards Proton by default because they'd rather have a well maintained Windows build running in a well maintained API wrapper, than a half-baked native Linux port that never gets updated, which is often what ended up happening during their earlier Linux-native push. I believe some games that did get Linux ports are now flagged by Steam to ignore that version and run the Windows version in Proton by default, because it provides a better experience than the port.
I seriously could not care less about proton, it is basically a gigantic and massive money sink hole and literaly disgusting software, actualy quite microsoft grade.
To make things even worse, proton is said to include a significant amount of software components directly copied from windows.
What actually worries me, is the devs from gcc and the glibc perfectly ignoring the fact that there has been games on "linux" for the last decade. The glibc devs have literaly a frenzy of GNU symbol versioning, breaking game binaries built on a recent glibc that on distro with a glibc no older that 1 year and half for no good reasons. Not to mention you still cannot properly libdl the libc itself, namely do a clean ELF dynamic load of it (maybe not true anymore, have to check). Unfortunately, many game devs have the c++ tantrum and the static libstdc++ from gcc does not "libdl" properly what it needs from the glibc/posix libs, and something tells me not to hold my breath at gcc devs fixing that.
So, I guess, I'll keep playing "linux" native games until windoz... I meant they force proton upon everybody for good, or until the glibc and gcc devs managed to make it near impossible to make reasonably robust in time and compatible across "linux" distros game binaries.
Actually, I got myself a simple C compiler and built a lean win64 with vulkan support from wine, useless, no windows game binaries are that clean, except maybe the ones from ID software.
