The last 4 symbols bugged out, when I collected them, 3 little circles at the top of the screen were not there and the game got stuck after each symbol The symbols were collected, but the achievs never popped and two more achievs (for all dots and for all symbols) never got unlocked as well....

Every time I try to play the game it shows this screen immediately after starting. The screen is unresponsive, I can't even close the game except stopping it from Steam https://steamproxy.com/sharedfiles/filedetails/?id=3357808535

For those of you that know what I'm talking about - what does this mean?

In the level select, level 5 is showing 2 unobtained dots at the end. However, in the level, the pause menus shows that I've found everything. I've checked through multiple times and I'm unable to find anything there.

The Linux x64 package of OVIVO expects the main executable to be called ../OVIVO.x86 and the games provides ../OVIVO.x86_64 so the game just not starts with the "missing executable" error. That's easily fixable though, just open the game's folder and make a copy of "OVIVO.x86_64", naming it "OVIVO.x86", and then the game will run just fine. You can even straightforwardly rename the executable file without coping it, but then the game will hiccup a bit on restart, redownloading original one to upkeep its...