Heads up, the original version of this game (released in 2016 as per the OP) was released separately as freeware in "Shrouded In Sanity: Freebirth" , links to Steam Store page.
The paid-for version includes post-game updates like the multiple playable characters, boss rush, wave survival mode... none of which I would say are worth the entry fee. It's a neat little game, pretty rough around the edges but the compact level design built around a single checkpoint really carried it for me.
Good atmosphere and pacing. Not so good writing or characters.