Aero the Acrobat 2 [SNES Virtual Console] Part 9 [Finale]
(Spoilers for another game in this description.)
There's a lot one can say about Edgar Ektor. How can there not be, when he's a maniac who probably murdered his parents in order to get an inheritance he then used to become a powerful industrialist, yet he dresses as both a clown and a comic book supervillain while using his wealth and power to exact revenge on circuses all because of something that he did himself.
He's also a surprisingly effective villain. Aero the Acrobat 2 takes place immediately after the first, so the failure of Plan A barely seems to have slowed him down. He learned from that failure, too - instituting plans to slow Aero down with interference from Batasha, Dr. Dis and Alter Aero bought him time to dramatically up his game in time for his second showdown with Aero.
Whereas the battle at the end of the Museum of Horrors in the first game was fairly simple, Ektor decided to put everything on the table in this one, and does it ever show. Plan B climaxes in an epic battle aboard Ektor's demented circus train, pitting Aero alone against an army of Ektor's henchmen, a merciless sequence of traps and weapons, and at the end of this grueling gauntlet, a final showdown between the two rivals that will decide the fate of the World of Amusement.
Ektor cheated death once, had plans ready on top of more plans, and escaped his defeat in this game to immediately begin devising his next move. If he didn't die at the end of Zero the Kamikaze Squirrel, then he is still out there to this day, having gotten away with everything he did.