Creating a Low Poly FPS Game From Scratch - Using Blender and Unreal Engine 4
How to stop FPS counter from flickering? - Discuss Scratch
Writing a retro 3D FPS engine from scratch : r/gamedev
Why does my games fps drop after playing it for a while? This happened on my first Scratch Adventure engine too, just not to this extent. There's a link in the comments if you want to try it out ...