Not very fun to battle the random-hits mechanic in this game. I do love the idea, just try working on that aspect a bit more, and maybe give a bit more variety to your enemies.

Why is the screen so small? Make it larger. The screen shakes and moves around, making it difficult to focus. Remove the random number of hits to kill an enemy.

Hey I'm working on a Roguelike in Construct also. "Bob's Discount Dungeon." Great use of minimal pixels and it looks like the enemies have very distinct patterns. I wonder what algorythm you used for the rooms. Anyhow good job!

After a lot of repetitive kind of dungeons, I've fallen on a "white screen dungeon" where I see only my spells...

It's an okay game, the screen shakes too much though, it gets really infuriating when you can't see shit because the screen won't stop shaking violently. Also all of my deaths are attributed to spawning up and getting mobbed before I even get a chance to see the screen I loaded into.