There are English write up and Korean write up.

You just need to implement the Emu2.0 with spec document.

I implemented Emu 2.0 with cpp.

I did some trial and errors because of something.

1. 4bit opcode / 12bit operand
2. endianness
3. memory (non)segmentation
4. undefined instruction

Conclusion: You need to read spec document carefully.

Original writeup (https://eine.tistory.com/entry/X-mas-CTF-2019-Emulator-Emu-20-Write-up).