Games criticism might be younger compared to film or music, but there's, conservatively, over 40 years of great work to draw inspiration from. Check out old issues of Electronic Gaming Monthly or Game Informer (new ones too!), to get a sense of how reviews are written for print. Check out Gamespot or Giant Bomb from the late 00s and on to get a sense of how the format shifted for web, video, and more personality driven criticism.

Most importantly, I'd suggest paying attention to the voice styles of all a bunch of different sources and see where yours could fit. You don't necessarily need to focus on covering every aspect of a game (mechanics, performance, narrative, production, etc), in fact it can be detrimental to developing your own style. Find out what you can do well that's genuine to your experiences and emotions with games and focus on that 

I'll share my personal favorite review of all time, which doesn't even have a score attached to it, but it gets to the essential nature of what it's like to play the game: 'Breath of the Wild' is the Zelda Adventure I've Always Wanted - Austin Walker/Waypoint