[Yes, a shame you cannot even correct typos once the review is published: GOG, let's edit them!]
So, I take the chance offered by this Deluxe Edition Upgrade to correct typos in my former review and praise again this game.
Do you like 2D hand drawn graphics? Do you like heavy metal music album covers, their aesthetics and their epic -and just a bit cheesy- take on Norse mythology and chivalric literature, mixed with modern dark fantasy? Do you mind a little humour in it? Have you just answered "no" to all questions? Well, you should try Slain all the same, because it is a challenging and rewarding game.
Take "Castlevania: Simphony of the Night" beautiful graphics and pump it up to the max, then apply it to a mostly linear level structure. Better yet, for those who remember it, take Psygnosis' "Shadow ot the Beast" approach to platform/action adventure and "Oh my!" visuals: Slain is indeed a worthy successor.
Difficult, at times very difficult, some passages requiring many tries and experimenting with your three different weapons/blades before finding the right approach; but, except for some very long areas and a multiboss without intermediate check points, Slain is usually quite balanced and not as infuriatingly difficult-for-the-sake-of-being-difficult-then-tell-users-it's-their-fault, as so many recent platformers tend to be (you know, the ones where developers and fans say "git gud" and try to simply get away with that phrase).
Then again, the reward is high: you will want to overcome any difficulties just to see some more of that beautiful, multi-layered art, parallax-scrolling by before your astonished eyes.
Notice I did not praise the metal music score: I enjoyed it for the first 30 seconds of every level, then it sadly becomes too repetitive and generic sounding. Let's be clear here: it is surely appropriate for the mood and for the whole Slain vibe, but none of the tracks really sticks to mind in the continually looping form that is offered during the game.
When listened on purpose and in higher quality FLAC format, though, you can appreciate more nuances and some of the tracks gain back in personality.