So, since the thread about the current feature poll is closed, I thought I'd quickly write a few words about that playlist feature, that is being considered.
I don't know how difficult it would be to implement that, so my idea could just be an additional thing that goes alongside that playlist feature. And it's also pretty self explainatory: A tagging feature.
I imagine it like this: Edit a game, there's a field for tags, much like the genre field etc., type in a few tags and save it. The tags you already used will now be listed with boxes that can be ticked (again, like the other fields)
It could be used to sort games by artstyle for example with tags like "pixel" "low-poly" "realistic" or atmosphere with "colorful" "spooky" "sad". Or the style of game like "cineastic/narrative" "casual" to better differentiate between games with strong focus on story and games that are more score-based.
Evenutally "Tags" would be another way to sort your games by, much like Genre, Platform, Developer, Publisher, etc. It's similar to the custom fields, I know, but I believe the way I imagine it, it would be easier to use and when the nesting feature is realized it could be beautifully combined with it. A silly example: Filter games that are single player, feature dragons (tag: dragons) and have pixel art.
Technically it's a request I guess, but I'm interested to heart what you have to say about it. I for one would find a feature like that incredibly useful.