Yes,but can you define truth subjectively?Someone can go to a thread of a highly popular game say-'This game is f.....g garbage/This is horseshit..etc',Is it not your personal felling projected as objective facts?Clearly the game is objectively not awful as its liked by a considerate amount of people.You can then say,those who like the game are brain dead 12 years old.What can you do?Not everybody played 100 different games on different genre's and obtained the true knowledge in adult gaming.Thats why different standards of adult games exist to entertain different knowledge niche.If a game is technically sound,then I say every game is good for different niches of people.
What defines a good game from a bad one is the work done in the multiple aspects of the game:
-Writing
-Gameplay
-Mechanics
-Cg's
Those can be seen clearly, of course some people may be more lax and easily satisfied while others you would need something divine for them to be satisfied.
There is a difference between liking a game and that the game is a good one. I don't critic that you like a game, but I can critic the game quality.
Having said that, not all games are good, but all games can be liked, even the worst game may have someone that enjoys it.
But what I mean to say is, to define a game as good or bad can be done objectively, but liking the game is subjective. And all you said is based on the subjective side and yeah, it's true, that's why it is different to critic a game and to be an idiot.
P.D: this is an example of a good game based on RPG maker:
First of all I always see the details, if you want to make a good RPG maker game you will have to cover those, I see the menus, see if the font is changed, the distribution, the stats...
Next I see the portraits for the characters and compare the CG's to the characters portraits, a good game needs armony in those, different styles or even mixing styles can result in an overall bad quality.
After that I see the combat, the changes it has, scripts...
Then I see the writing and the overall story, if it's a bad one, average or a good one. The difference is that in the bad one, it just doesn't make sense, the average it just gives enough information to motivate the player to advance the story, the good one requires to be interesting and that people can enjoy it.
Obviously you have to see the art and the assets used in the game, there are many free resources for RPG maker games, even more some can be bought.
Finally you have to see if the game introduces something different to the usual, for example side activities like having a farm or doing various things.
Those are general lines that I follow before I can say a game is good or bad, as a summary those are:
-Care to detail
-Common art style for all aspects, or that there is armony between different styles
-Changes to the scripts, menus and overall changes over the basic ones given by RPG maker
-See that the writing follows logic and it isn't all over the place
-Existence of unique assets or use of the free resources that are for RPG maker
-Existence of other interesting or unique activities outside the main plot.