Retro Golf, which is part of St. Louis Escape Room, has the coolest mini golf course my family has ever seen. My kids didn't appreciate the 80s/90s theme as much as my husband and I did, but they loved the unique course.
The location is a little hard to find. You enter on the far right side of the building and walk up 3 flights of stairs. They're only open when there are escape room and/or mini golf reservations, so be sure to book your time slot before you head there.
We booked the first time slot of the day (3:30 pm), which worked well because it wasn't a popular time and several groups were just starting mini golf as we were leaving. My kids also enjoyed playing pinball while we were there (each game is $1.00).
There was plenty of street parking available when we visited. It's $2.00 per hour, plus the ParkMobile transaction fee. Just one block away from mini golf is Pieces Board Game Bar & Cafe, which we went to afterwards and loved!