Well from a game design perspective:
It's fair if you don't like the Igniculus system in combat. That's a nonstandard component, and different people like different things.
The 2 player limit is actually needed. Since you can swap players mid fight, you actually have everyone for every right, but if you had more than 2 people out at a time, interrupting enemies would be too easy. Bosses would never get a turn.
As for the skill tre...
To be fair, the reviewer didn't perform a standard playthrough. In a game that is only 4 hours, to grind out 3 Princess Stones for everyone would mean you're spending 15-20 hours grinding. Any RPG is trivial at max level, so saying it's too easy after doing that is not really a valid review.
The game structure was simple, but at least it should have received a 4 or 4.5/5. Given it costs less than ordering a pizza, I personally think it should be a 5/5 for the cost...
Totally, but the $15 price tag justifies the short length.
It was honestly fun enough. Like, the combat was responsive and generally smooth enough. So if you're in it for a quick hack and slash experience, you'll probably be able to stay interested for the duration of the game. It's pretty short.
It just lacks any sort of depth or narrative quality.
All the bugs and balance issues don't take away from the fact that "fighting can be fun".