Godot provides a huge set of common tools, so you can just focus on making your game without reinventing the wheel. It is completely free and open-source under the very permissive MIT license. No strings attached, no royalties, nothing. Your game is yours, down to the last line of engine code.
This is a companion discussion topic for the original entry at https://copr.fedorainfracloud.org/coprs/rluders/godot/