Godot is a free open-source 2D and 3D game engine with some friendly, powerful features. The engine itself is very small – under 1 MB – and even with demo games and assets the download via Steam is under 1 GB. Godot is a great option for developing on laptops or older PCs/Macs.
YouTube tutorial: Introduction, examples of Godot games on Steam and instructions to build the maze game shown above.
Coding can be done with GDScript, C# (like Unity), C++ (like Unreal) and visual scripting.
Installation is much smaller (at under 1GB) than Unreal or Unity. Either download from the link or install via Steam: