The fact that the review acknowledges the game is not perfect and yet it gets perfect 10/10 scores across the board.
A 10 doesn't have to mean something is perfect. In-fact, unless the numbers on your scale are intended more as labels than to represent a linear/curved numerical scale (which is a perfectly valid system, but clearly not the one Aldro is using), i think it's pretty illogical to define a 10 that way. There is likely no such thing as a perfect game, thus 10 would become undefinable. Without being able to define both ends of your scale, everything in-between becomes meaningless. You'd basically be saying "I give this game [x] out of perfect", or "this game is [x]% perfect". It doesn't make much sense when you have no idea what perfect means. You might as well give something 6 out of apple, or 9 out of paper bag.
I wouldn't personally give UC4 a 10 (As of chapter 15 i'd give it a 9.0, but if it maintains its current quality through to the end, and wraps up the story nicely, i could see myself giving it a 9.5), but a 10 is what Aldro thinks it deserves, then that's what Aldro should give it.