10/10 is I cannot find even one thing wrong, and thus, cannot imagine how this could be better. Perfection. GOAT status.
9.0-9.5 is Outstanding. Exceptional. GOTY material. Establishes a standard by which all future games should be judged henceforth.
8.0-8.5 is Greatness, Excellent. Worth playing at full price.
7.0-7.5 is good/neat/interesting--only fans of the genre or IP might want to pay what they consider "full price"
6.0-6.5 above average--either the developer tried hard and missed the mark or the dev did enough just to get buy and it shows
5.0-5.5 average--there is better and there is worse. Causes ambivalence
4.0-4.5 below average--this is where performance issues show up such as FPS drops/slowdown, screen tearing, and PSX-era textures (pixel art can be okay, but yours is trash), and OG Resident-Evil tier VA show up. Music and FX are annoying if not inadequate or absent
3.0-3.5 game is bad. If you were not writing a review, you would be asking Valve for a refund...unless you're playing on consoles #selfpwn
2.0-2.5 You actively hate playing this game, and thinking of ways you could nuke it into orbit is more fun than actually playing.
1.0-1.5 Game is literally unplayable. BSODs, DRM problems, crashes, save deletion, always online service that can't phone home. Also, plagiarism (if you're going to pay homage to a beloved franchise, you had better say so in your promotional materials!).