Hot air balloon, since it’s the less common experience
would you rather

I would not make a 4D game from scratch. I could spend those hundreds of hours playing blitz and finding ways to refute my friends’ opening repertoires. However, I’ve always liked the idea of coding so I would do a 2 or 3D game (if I was able to learn how)

Would you rather get every achievement on chess.com or would you rather not get any achievements on chess.com

Bots play very unnatural moves, for better or for worse. Don’t get me wrong, I do play the monthly bots.) I focus on improving, and you improve by playing training games vs. your fellow humans. (Preferably 100-200 points higher rated than you, to keep you on your toes while still giving you a chance. The likely result is that you win roughly 29% of your games against them.)
Also, OTB is better than online chess. Change my mind.
Zip lining