Your feedback is appreciated but if somebody is specifically reviewing volume 1 of a series and not diving into the myriad source material as well, they cannot backfill information from future volumes or other media that they haven't read; it's not a full series review and nowhere does it claim to be. The review specifically says "within this first volume, we don’t truly get to know anyone except for Sara and Joe. This does the manga no favours in terms of getting us attached to the cast, but that’s not the only problem with them either." which I feel is very clear. Perhaps the original mobile game is amazing, but the reviewer clearly felt that the manga version was lacking in this department and proposed a possible explanation (which you are saying isn't the reason, in which case the manga has just done a weak job of presenting the material).
For some reason we get quite a few of these comments defending content without properly contextualising the review or seeing things from the reviewer's perspective. I completely understand how annoying it is when you love a series and someone gives one of its spin-offs a critical review, but at the same time it seems that this first manga volume doesn't actually stand up very well on its own - and if that's the case, the reviewer has a duty to give their opinion. Please do feel free to give a contrasting summary in this comment thread to entice people who might love the same elements that you did!
R