He licensed his code, which is kinda strange since he took the algorithm from another program which he didn't owns.
I wonder the real legal status of his code and license
Unless there was a Mega Man code patent (clearly expired if there was) then it would seem just fine. Nothing wrong/illegal with re-implementing an algorithm in another language.
Algorithms are patented, not copyrighted.
strictly speaking, in theory, algorithms aren't patentable, only specific implementations of algorithms. In practice, it would seem, lawyers figured out a way to do it with some clever wording. "Method and Apparatus"- You see because the method on its own is not enough to patent you have to include the computer that the algorithm runs on in the patent, in order to patent it.