How do sites with tons of games of popular engines like Game Maker, RPG XP, and AGS work out their games listings?
By building a system for users to vote on all the games, discovering that this system completely sucks and returns no useful data at all, giving up, and having the staff pick a few games that they personally think are great.
If you play City of Heroes you can see some of the same problems coming in with the user-written missions system. Letting people vote on games sounds like a simple solution, but soon you end up with crazy spammers demanding votes for their games, crazy blackmailers demanding that you do what they say or their whole guild will one-star your game, and no clear way to tell apart the twenty thousand games which all have a four-star average. I can't speak for RPGmaker or AGS but I know GM has had problems in this area.
It's hard to make a list because is subjective. Probably would make more sense divided into some categories like "best stories", "best art", "best soundtrack" etc.
'Best' is still subjective and can lead to arguments or hurt feelings.
Possible suggestion:
Take all games that meet the vague quality thresholds stated. Look at each title. Determine what's notable about it. If you can't think of anything notable about it, discard. Display all the rest of them with their brief description and reason(s) for notability.
Reasons for notability might be an interesting art style or gameplay mechanic or really good story or all sorts of other things. If possible, allow user to sort by notability reasons, so that if they want to find something with good art they can.
But being clear that it's notable rather than best means that one can show off, say, a game written by an insane artist in brain-melting colors and bizarre effects and custom interfaces and say that it's NOTABLE for its style without having to have as much argument about whether everyone LIKES that style. 'A Game Of Interactive Psychedelia' might be clearly notable as an example of how much you can do with RenPy outside of the standard dialog box setup, but also clearly be NOT what the population as a whole would vote as 'best art'.
Troll...