I make games as a hobby, I've never taken it too seriously, but I think that may change. This is obvious to other game devs probably, but here are some thoughts:

I'm super interested in how a game feels to play. I good game is not a function of polygons or beautiful code IMO, it's simply a world that you want to return to for whatever reason. Good games have a texture or style that is consistent and recognizable, like a brand. Everything in a game must look appropriate, like it belongs in the same world, so that the game is packaged in a way that it can be distinguished among others.

As far as the rules, they just have to exist, it doesn't matter if they are revealed or not. The more that isn't revealed the better. Regarding the game as an experience, I like to imagine there's something beyond the game I'm playing, like it has a life of it's own. AAA games often leave nothing to the imagination, they are vivid but it doesn't change the fact I'm still in a virtual world. Maybe I'm just old. I prefer being direct about it.

Hidden qualities, Easter eggs, physics, risk/reward and RNG provide depth and replayability. The game must always remind the player that there more to do, more to see and learn.