The challenge
This challenge was fun. It was a NES ROM image that contains the famous game — Battle City. After quick examining the ROM in a hex editor we did not find anything useful, so we decided to run it. Emulator used: FCE Ultra v0.98.13.
Booting the ROM
Startup screen:
Finding the flag
When we played it we tried to dump ROM memory (trying to find out the flag, but not succeeded). And when the 1st level was done we got the flag:
There is a little bit of brute-forcing in the answer because the flag 8 bit rules was not the correct submission. After trying different versions we landed on the flag: 8BIT_RULEZ.