I like your choice in colour pallete. Very foreboding.
If dungeon is so impressive on outside, I really love to explore the inside.
-Except I would be the person who die first.
Looks like a dungeon with a continuous poison debuff. Best bring tons of hp pots. 
All your "enter the dungeon" pieces are amazing. They all give me the sense of dread one would expect before entering a den of evil. Great work!
Really nice! Your style reminds me the thu style, really good!