Regions of ruin 75% off (steam store)

Mweh doesn't really tell me what it's similar too.

Okay well Kingdom: New Lands but didn't play it, so still don't know if i would like it.

I believe its just a kind of promotion. - "Jajaja, I made a mistake, so cheap, run and buy! "

Dev gave few keys for free (I know ppl who farm cv with devs keys here), dev sold many keys to resellers (game never bundled but u can find keys almost on every site u check).
/friend gift me key for this game few hours ago, forgot to ask where he got it xD

developer made so big mistake by accident

It has already been 75% off in the past, so even if there was a "mistake", it wouldn't be a "big" one. :P

looks like a great indie game

It does, but going off negative reviews [outside of the couple which are nonsensically griping about protagonist gender options], it seems to have the same issues with quick-onset gameplay repetition (ie, lack of added depth past initial content) that Kingdom has, as well as some imbalanced mechanics and bugs/design quirks (again, rather similar to Kingdom). It looks good, especially to anyone who is already familiar with the flaws of Kingdom, but purchasing probably'd be best done under the consideration of it not being a fully polished game.

Kingdom (or at least, its "Classic" version) was free multiple times, in addition to the game having been bundled, so those who are on the fence about Regions of Ruin may find it more agreeable to try and find a spare copy of that game to try first, to first see if the general premise is favorable (as Regions of Ruin seems to be a close mimicry of Kingdom, down to having the same kind of graphics, flaws, and issues, with the exception that RoR adds RPG elements (ie, item drops and basic player combat) and seems to be a fair bit more actively engaging overall than Kingdom).

"Mistake"
I'm not judging, but considering how much choice you have on steam when it comes to indie, its easy to get overlooked.
passing it as a mistake, might get a few more copies sold than quietly discounting it