Fighting the boss, I was standing on his arm and shooting, then I fell through his arm off the screen, I did not die, I was simply off the screen, I was then forced to restart.

So I reach the last level and there's a unbreakable barrier at the end with no way to progress. Is there something I miss or is this a bug? https://steamcommunity.com/sharedfiles/filedetails/?id=1786874553

will there be Steam Achievements in the game when it's released?..thanks in advance for your time and good luck with this and future projects..