My Suggestions

[Aevumas]

Summary
Here I'll present my ideas first with the reason for their conception and then the ideas themselves.

Reason: I was playing the demo and soon found I just wasn't buying things, and accumulated a few thousand gold. The easy fix is lottery for good weapons, but really that's just boring. Besides, it is very finite.
Solution: Arcade

• A series of pre-designed (not-random) levels which constitutes an in-game arcade.
• For example, take all the levels of Super Mario Bros. and remake them in Chasm. Have blocks that when hit drop stone dagger / iron sword; bandana / leather helm; leather vest / platemale.
• When you start playing you have an empty character every time, continuing costs gold from the actual game. Booting up a game costs gold from the actual game.

Reason: Bats are annoying. They will mess you over, but in order to deal with them you have to be patient. I don't like being patient. Besides, it goes against the point of the game to spend a few seconds sitting around waiting for bats to enter your hitbox.
Solution: Taunt

• Book of Insults or something like that. An ability that uses 2 mana points.
• Within some radius (64 px maybe), enemies will take 2 damage and receive +2 strength. Takes care of bats easily, worms, but you have to use carefully.

Reason: Right now there's not much use for having more than one weapon except waiting to sell one.
Solution: Duel Wielding
Does one of two things:

• Increases damage to the sum, you can use both for either animation or hitbox, but the same damage is dealt.
• Both attacks will be dealt much quicker than usual (1 tick, frame, or whatever. Maximum speed), if [S] is pressed then the attacks will be in sequence, if [D] is pressed then the attacks will be in the current direction and the opposite one. This will pause horizontal movement.

Reason: The tiles are a bit monotonous. Of course this will change, but here's my humble suggestion. Besides, it seems original yet relevent.
Solution: Mountainside Tileset

• A tileset consisting of the mountainside. Snow, scaffolding, pits and cliffs. You get the idea.
• Variance: Springs, botony, mysterious carvings.
• Snow covered chests and chests hidden in snow drifts.
• New variance of enemies (doesn't have to be, but gives ample room for)

Reason: The room types are a bit monotonous (again of course this will change). Here's one that fits in perfectly, and if thought out, is to be expected.
Solution: Pits / Caverns

• We've probably all seen those rooms with the pitfalls. Kind of bottomless. But have we seen rooms with open ceilings?
• Rooms without ceilings, and sheer walls- these would be the pit bottoms.
• Rooms with lots of space, such that you can't access it all. Like the 2x2 rooms, but less stuff in the middle. Maybe 3x2 or 3x3. These would be the caverns.

I may add more later, but I wanted to put these up before going to bed and forgetting them.

[Eion Kilant 739]

I disagree about that taunting thing, if anything it should cause enemies (within range) to rush you (in a line or shortest path) with a slight damage bonus. Bats also aren't really that difficult to deal with so long as you time your jump-attacks just right, IMO.

As for the buying problem, something akin to a recall potion will probably be the best... Though it's got to come at a high price.

EDIT:

Yea, we're going to implement a portal system, as well as have scrolls that will recall you back to town immediately. Thanks!

[Geko]

Can't really agree with the Taunt and Arcade suggestions but changing Pitfalls is a good idea. Pitfalls themselves is a bad idea in my opinion as I've never liked them in games. But if dropping down them actually puts you somewhere else then they might be okay. Respawning at the start of the room was not a good solution for them.