Impossible mode is nowhere near impossible enough.

[BluJaguar]

Some suggested changes (implementing all of these might be overkill ;):

Dim the lantern, give it 'fuel' that runs out over time, make it always to 1 damage regardless of strength, or eliminate it entirely. The dark isn't scary enough once you get your strength up a bit and can just run around with your 450 dmg 'dagger of light'

Remove all of the ambient lighting from the dungeon. Only real light sources should illuminate your doom.

Mute the aggro noises that enemies make. Knowing that something is coming and what it is gives you time to react. pffft.

Remove the big heal potion, several-apple crates, book of random, and book of reapers from the drop tables.
· Big heals are too generous for a hard mode. I would replace the big heal potion with a poison potion. (negative small heal)
· Crates-full-of-apples are nearly equivalent to a small heal potion. They should be much more rare, or only heal 1 hp.
· Book of random is too easy to exploit for exp, potions, and money. If used carefully, it can make hard-mode into easy-mode. One change that could help would be to make enemies that spawn from the book auto-aggro on the caster. (as if the caster farted)
· With spawning on pretty much every floor your odds of getting a book of goes up dramatically; at least limit the spawn to 1 .

Add up/down movement in addition to left/right. (Needs forward/back sprites, tons of work for Alix. >_>) Most tough enemies are not able to strafe quickly, their movement patterns and field of view limitations are easy to predict and avoid. Allowing forward/back directional facing and movement would dramatically increase the difficulty of avoiding enemies and their attacks.

Make goblins steal a random item from your inventory on hit. (including equipped items) ... this would make them genuinely dangerous instead of just mildly annoying.

Always spawn a boss in the room where stairs go down.

[Masternine]

As challenging as that sounds, I believe after some time no one will ever play this mode except for showing your friends how to die in different awesome ways.

[MoebiusJones]

I play it daily. It brings back the feeling of hilarious surprise, when you walk into level one and can't get through the first room because 5 Reapers are blocking your path.

I usually try the Daily Dungeon, but if I fail, I have a quick crack at Impossible Mode. I've made it pretty deep, but am yet to bring back the treasure.

[MoebiusJones]

OK, finally brought back the treasure on Impossible mode.

That felt like flipping a coin, and trying to get heads 10 times in a row. But fun!

[HaidrGna]

There is an impossible mode as well (cannot seem to find it though), I find the current mode already quite challenging :)