It is actually somewhat painful to look at -- and I say this as someone who plays DF and pretty much every roguelike where it's an option in ASCII -- but as a game qua game? I'm hooked.
My last dude died to a Snapjaw Firesnarler, who had set about half that cavern level on fire, including the walls. I burnt to death, because not only is shale apparently flammable, so is Jack. Jack was quick, had a beak and burrowing claws, spat electricity everywhere, and had multiple legs. He murdered over a score of hyenabolds (aka Snapjaws) through zappage and bludgeoning of the claws and staff. He slew a number of crocodiles, glowing fish, and what are apparently voracious mutant lilypads. He died to fire.
My next character, also named Jack, has spinnerets, multiple legs, and an exoskeleton. He (or she, I guess. Gender doesn't seem to be defined.) also can regenerate lost limbs. Through a quirk of mutation, Jack has gained the detriment Evil Twin. Somewhere out there, a parallel version of Jack travels through time and space to destroy him.
I have not yet moved more than 2 map squares from the starting town. Despite this, I am impressed.
EDIT: For those looking to get started, travel south two areas and kill some glowfish. Bring the glowfish back to the trader (Press ?, then check the 10 things) to sell for water. Use the water to buy needful things, then go kill more glowfish. Beware the lilypad things, because they apparently hit pretty hard, or something. Also watch out for crocs and more dangerous things as you expand your hunting area.
Starapples sell pretty well, if you've got harvestry. They're the red yen signs =p