For something that is not an open world, action adventure type of game, as in, the use of surround sound will not be beneficial to the player or game mechanics, I'd just make a typical stereo mix.
Balance and system check as normal, main monitor mix on typical studio monitors, checking to make sure it translates to smaller systems and headphones/earbuds.
From the gamers that I know, I'd have to guess that most older players are listening on TV speakers or home HiFi where as younger players are using headphones or headset/mic units. Looking at the current demographic of gamers, that split is probably close to 50/50.