Now, many who played an escape room are creating their own. “But having $10,000, a dream and some moxie isn’t necessarily enough to make a business,” Mr. Spira said.

Successful entrepreneurs have relevant backgrounds like engineering and psychology and the ability to learn a variety of new skills, like accounting, game design and set building.

Andrew Preble, who founded Escape My Room in New Orleans, drew on his past working at a technology start-up and operating a restaurant in Berlin. Mr. Preble opened his first escape room in 2015 and now has four games that revolve around mysterious events that happen to a fictional old New Orleans family called the DeLaportes, inspired by Marguerite Delaporte, one of the conspirators accused of poisoning Louis XIV in the 1600s.

Mr. Preble said he knew starting a new business would be hard, “but I didn’t expect it to be as popular as quickly as it was.”

Demand was high enough that six months after opening a room called the Jazz Parlor in 2016, Mr. Preble built a nearly identical room for corporate groups and birthday parties. The average number of monthly visitors increased 29 percent from 2016 to 2017, Mr. Preble said, and his team now includes eight full-time and eight part-time employees.

Despite the rising popularity, getting a bank loan to finance the business can be a challenge, Mr. Preble said. “Lenders still don’t exactly understand what escape rooms are, so it’s difficult to assign value to this as an asset,” he said.