MiSTer with BlisSTer
Most people are used to emulating consoles and computers on their modern PCs with something like MAME (Arcade), Spectaculator (ZX Spectrum), Dolphin (Gamecube). These are fantastic and pretty much indistinguishable from the real thing, however at the end of the day they are still relying on rewriting logic from hardware to software, and it will never be a 100% recreation of the original hardware.
Enter in FPGA. FPGA in the simplest terms is a perfect reproduction of the original hardware. It consists of groups of programmable logic gates, memory, or other elements that can be changed. Because old consoles and computers were relatively simple by todays standards they can be perfectly reproduced on something like a DE10 thanks to the diligence and hard work of the core maintainers who put a incredible amount of work into replicating these systems.