If you're successful you'll be talking to multiple lawyers. As a hobby grows into a full business, and as the business grows to hire workers and do even more business, you'll end up developing relationships with many different lawyers.
You will be talking to lawyers about standard business issues, talking about corporate law, talking about employment law, talking about tax law, talking about game industry contracts and IP law both in your country and internationally, and you will occasionally need to talk to lawyers about other concerns as well. For those last two topics, game industry contracts and IP law as it relates to games, you will want a lawyer who deals with them extensively.
I would not expect your game industry lawyer to be the same one you talk with about your employment contracts for example. They are different specialties. Your lawyer who is expert on South African employment law will be a different person from your lawyer who is expert on South African and international IP laws. You might end up finding a law firm that has lawyers with both specialties, or you might end up working with multiple specialists in different firms.
At this point of starting out, unless you have specific recommendations for or against a specific firm there isn't much reason for either red flags or green flags. Talk to a few, learn about their prices and services and areas of expertise, learn about where their offices are, if they're likely to be in business in 20 years. Take the info, make a decision grid, rank them based on whatever criteria you feel are important, then ignore it all and pick one at random. ;-)