Which Sega Genesis title’s secret difficulty level (hidden “extreme” mode) challenged your skills?

[killamch89]

Many classic Sega Genesis titles hid secret difficulty modes or extreme challenge levels unlocked through codes or achievements. These hidden modes ramped up enemy aggression, limited power-ups, or altered mechanics to test seasoned players. Finding them felt magical. Which Sega Genesis game’s secret “extreme” or hardest difficulty mode challenged you the most? How did you discover it - through rumor, manual hints, or trial and error? What tactics and loadouts did you rely on to conquer those amplified obstacles?

[Scorpion]

For me, Streets of Rage 3 had a seriously challenging hidden difficulty! Beyond its already tough normal mode, getting the true ending required you to beat it on a specific, higher difficulty without losing a single continue. It truly tested your mastery of the combat.

[killamch89]

Contra Hard Corps' hidden "Expert" mode was absolutely brutal - enemies fired twice as fast, power-ups were scarce, and one hit meant death, but mastering it felt like achieving gaming nirvana and proved you were truly skilled.