No more unto the breach
More than five years later, Chasm finally got released. It's technologically solid, and has a nice, clean art style. That concludes the nice things I can say about it.
Chasm just isn't fun.
Combat, for starters, is somehow simple yet clunky. Attacks are slow and can't be canceled - not by jumping, not by an evasive backward-dash - so most of the damage I suffered was well-telegraphed, but practically unavoidable. Chasm abides by an antiquated combat design in which you must jump, then attack to preserve mobility -- not just silly and cumbersome, but impossible in some cramped corridors or over rough terrain.
Chasm has some elements of RPG progression, but doesn't execute them very well. As you delve into the mine, you'll earn experience points from killing enemies, collect coin for purchasing upgrades, and gradually rescue townsfolk who can craft said upgrades. But leveling up is slow, and grindy; collecting enough money for upgrades also feels grindy; and critically, good upgrades seem to be locked behind finding and rescuing the Blacksmith. Until then, the only way to get better weapons or armor is random chance from enemy drops (which, again... feels grindy).
Some rescued townsfolk also prod along the game's underwhelming attempt at a story. The light prologue, some collectible journal pages, and scant dialog all hint toward a backstory that's ... not very interesting. Some legend about an old king and an apocalypse cult, and then -- oh, you awakened an ancient evil in the mines? You don't say.
The game's world feels overall uncreative and empty. The mine's levels are blatantly inspired by Diablo, not only in how they change themes as you descend, but also in how they're procedurally assembled. But while Diablo's randomly-arranged rooms showed "character" through the enemies you fought there, Chasm's enemies aren't that engaging, nor is anything else happening in its bland, interchangeable levels.
(There are a few environmental puzzles, but nothing comparable to, say, a Zelda block-pushing puzzle.)
Chasm wears its Diablo and Castlevania inspirations on its sleeve, but fails both to replicate the highlights of its predecessors, and to introduce any unique strengths of its own. It's admirable, for a Kickstarted game, at being technically playable; but I couldn't give a good answer for why you would play it.
Better than: Bear Simulator
Not as good as: Torchlight, or maybe even SteamWorld Dig
Arguably on-par with: Shaq Fu: A Legend Reborn
Progress: Gave up in the catacombs.