In all genres, I keep hearing about how the current level we (the lobby of players) are on is bad/good; but I don’t understand how the map is bad/good.
I think one the leverages the game’s mechanics in a fun way. I live that one map on halo with the two giant buildings across a field inside a canyon from each other because you get up close combat, vehicle combat, long range combat, it’s just all great fun
It highly depends on the type of game, but as other said any map that explores the game’s mechanics in a fun a creative way is a good map. It’s a broad description, but it fits all genres. Good puzzle levels are usually very creative in their use of mechanics, multiplayer shooter-likes allow for an interesting diversity in gamestyles and loadouts/classss, etc
The thing to consider IMO is if it’s a singleplayer or multiplayer map, as there are different goals in mind when greating these maps.
With singleplayer maps, it’s supposed to directly engage with the player (incl. AI/bots). Meanwhile multiplayer maps are meant to let the players engage with each other in the best possible way (such as balancing and guaranteeing a level playing field).
But of course it also depends on the type of game as well.
Watch mapmakers’ making of videos, e.g. what 3kliksphilip thought about while making de_sparity for Counter-Strike Global Offensive.