ecl and gcl compile to C. That's fine, but not necessary to merely use C libraries; for that you need a C foreign function interface (FFI), which most surviving CL compilers offer. C++ is more of a challenge, hence the Clasp project.
I feel like Clasp has huge game development potential but has gravitated towards science just because that's where it came from. Like surely one could use it to get good godot bindings for example, but I haven't seen stuff like that around.
