so my first thought is "Why would Sega have a RPG made of early Phantasy Star instead of of the more well known and and equally distinct Phantasy Star Online" So I assumed these guys sought out the license from Sega instead of Sega seeking out them.
My second thought is "on the surface this looks like 5E"

since it says powered by Esper Genesis and their twitter name says Esper Genesis 5E
tt sounds like they're reflavouring a game they already made into phantasy star, which isn't unusual. but I since I never heard of Esper Genesis the 5E there could also just mean that Esper Genesis is actually old and also on its 5th addition. A lot of older games seem to be around 5 or 6th editions.

So I googled
Esper Genesis 5E is a heroic sci-fi tabletop roleplaying game powered by DnD 5th Edition. Produced by Skydawn Game Studios.
and that answers that.

as far as I know theres nothing innapropriate about making Phantasy Star using 5E. I only played the Phantasy Star Online/Universe. But from what I understand original Fantasy Star is some classic swords and magic fantasy rpging with a space fantasy sci-fi element. DND 5E probably would do the job just fine. Lots of people love 5e after all, but not very exciting

Whats getting to me is that Esper Genesis from what I googled is already built off 5E, and this is powered by Esper Genesis. So does seem like they're basically making a re-flavor of their own re-flavor which does not make me think very highly of them.

Their third project is also for bridging whatever gap there is between base 5E and Esper Genesis. So it would seem all 3 of their projects are space fantasy 5E projects.

All in all I went from "this is interesting" to "this is entirely uninteresting" pretty quickly.

It turns out the basic rules of the game are free, and I decided to check it out to see if there was hope for the Phantasy Star game. I don't think I've ever seen anything that made me think "You designed the game wrong" as fast as that chart above. But as I read more on the class, I realized why it was like that. It's a cleric. Like it's a wisdom based full caster with healing spells that gets medium armor unless they take a subclass that gives them heavy armor, and they basically have channel divinity stuff against undead except now it's an EMP against constructs. It's a cleric except they replaced the fantasy words with sci-fi words. And that's basically how the other three classes in the basic rules are as well. Specialist and Warrior are just Rogue and Fighter, and while Melder is clearly a wizard, they did at least have the optional spell point rule on for them by default rather than Vancian casting.

I admittedly mostly skimmed this, but it looks like the kind of lazy, half-assed shovelware 5e product I was afraid it might be. If you can figure out how to reflavor existing D&D 5e things to seem more sci-fi, then you can already do 95% what this book is charging you money for. I do not have high hopes for the Phantasy Star game.