by looking at the thumbnail (the small picture on numa), it doesn't look to aesthetically appealing.

(picks random map)
this one [nmaps.net]
if you look at it, it just looks... cool. it's hard to describe really, but you can just see that it's really neat.

The tileset plays a HUGE factor at this, and usually some recurring theme or element in it makes it look very good.

Secondly, your object placement can't be too strange. Keep it consistent, and focused. And try to avoid those lines of mines, especially the ones at the top, and ones that really serve no purpose whatsoever. Try eliminating unnecessary elements of your map, like the 3 floorguards, and the mass of mines that made up the teeth.

But yeah, stuff is really happening with your map making skills. Again, tey keeping the same types of enemies, and a limited number of them to cause the most fun & challenge for the player. You don't need many types of enemies squashed into a map to make it fun.

nice stoned face.

.

(that's a really creepy smiley)

slooooow down your mapping pace. a little more thought into your mapping, and how it looks.

People won't play your maps if they don't look good.

People won't continue playing your maps if they aren't fun.

Balance!