Slain is pretty good now. Only took about 4 hours to beat, but it was a nice, challenging romp. Level design is a decent mix of action and very light platforming to break up the pace. Bosses are disappointingly easy, though the last one is a bit tedious. Aesthetically, it definitely commits to metal throughout, and it hits more than it misses. Some of the fire and running water effects look out of place, though. The soundtrack is easy enough to bang yr head to, but I wish it covered more subgenres rather than sticking to thrashy riffs for the most part. The non-metal music is surprisingly good at setting up the mood, and weirdly enough I kind of wish there was more of it.
Overall, if you're into metal and/or deliberately paced action platformers, go for it.