A Unity Arcade VM with specific hardware and programming logic.
Why not? This program implements a completely virtual old-style hardware that can be used to run small games. The computer is high-level and offers a powerful features in a simple mode.
It is done with Unity (2020.2 at current time). The hardware specification and the software structure is inspired by old computers consoles (like C64, Genesys, and Super NES.) but with a modern touch you find in contemporary game engines.