Review scores are close to useless for the only question that matters, which is whether you specifically will enjoy this. Two games with identical scores can be indistinguishable in quality and completely different in whether they are for you. These checks are more predictive.
The fifteen-minute rule
If a demo exists, play fifteen minutes and then stop. Not five, which tells you about the tutorial, and not an hour, which tells you about the difficulty curve rather than whether you want to be in this game.
At fifteen minutes you have learned the core loop. Ask yourself one question: would you play this loop for two more hours without anything new happening? If the honest answer is no, no amount of later content fixes that.
Watch someone else play
A full playthrough video, unedited, tells you more about pacing than any review. Watch it at double speed. If you are bored at double speed of a game someone else is genuinely enthusiastic about, you are going to be bored playing it.
This also reveals the ratio of walking to interesting, which most store pages and reviews completely fail to convey.
Read the recent-owner reviews, not the average
Store review pages let you filter by recent reviews and by whether the reviewer owns the game. The useful number is not the overall score but the recent score among owners, which is what tells you whether the game holds up after the first impression wears off.
A game with a middling recent-owner score and a high all-time score has degraded. A game with a low recent score and a high overall score may have been review-bombed, which is worth knowing about but is a different problem.
Check the platform requirements
Minimum specifications on a store page are frequently wrong, and the difference matters. If a game lists a 2015 processor as a minimum, that almost always means it runs at 20fps on an integrated GPU and the developer listed the machine it launched on.
Look for a recent video of the game running on the hardware you actually have. This is unglamorous and it is the check that saves you the most money.