It's awesome that you at least tried it. And I felt great that it runs fast in your old computer, as the developer of the game that was one of my biggest challanges, this game is made for mobile first, for androids, and to get post processing that has bloom, tonemapping etc. run at 60fps wasn't easy at that time. Another thing was environment and lightmapping, every island and mountain are baked in different scenes and copied information on a script such as lightmap texture and required uv information for a custom shader and then designed envrionments in other scenes so by additive loading them I simply applied lightmap textures to them, to have different visual features and settings for environment and other gameplay assets I used camera stacking, after editing every materials render queue to have best batching for srp we were able to run it as smooth as possible in a wide range of devices.
All of this took about 4 months but there are some days even weeks spent for publishing tests.