A mashup of classic shooter Wolfenstein 3D and silly arcade romp Super Monkey Ball is ridiculous. It shouldn't work, any rational person would say. Return To Castle Monkey Ball is indeed ridiculous but somehow it does actually work. You can find out for yourself by rolling your way through this fan project for free right in your browser.
"Fight your way through eight procedurally generated floors to escape the fortress," says RTCMB's creator. "Collect bananas and treasure to maximize your score and defeat guards for time bonuses! Just get to the end before the timer runs out! Lose all three of your lives and it's game over for you."
Return To Castle Monkey Ball does indeed have that classic Wolfenstein 3D look with stone hallways full of dudes in helmets. You'll not be punching or shooting your way out of the castle though. Bubble bonking is the new weapon of choice and bananas are the fuel to up your score. Don't miss the cute easter egg in the high scores, either. You may recognise some of the supposed top players. Apparently some folks are already speedrunning RTCMB, even. Of course they are.
I gave it a try myself and it absolutely did not go well but I'm quite confident it's because I am bad, not the game. Apparently the difficulty level "Don't hurt me" is still a bit above the skill level of a person who has neither Wolfensteined nor Monkey Balled before.
You can try your hand at escaping the Monkey Ball castle with your guy B.J. over on Itch.