I contacted the testers, and I decided to give testing more time.
So deadline for testing now is June 16th.
I have also decided to make things a bit easier for testers.
I made a patch that fixes some minor problems: less lag at some points, more items, less difficulty, more instructions. Just extract the rar file to your game folder and replace the previous files.
DOWNLOAD TESTING PATCH
I also wrote a very brief guide for those who are stuck at some point and don't know what to do next. I recommend you do not read it unless you're really stuck. Also, don't read past the point you need.
If by June 16th I don't have enough savefiles, I'll release the game as it is. I have fixed some problems according to the testers feedback, but I haven't implemented the system that would require the savefiles I'm asking to function. If I don't have the savefiles by then, the game will have to do without it.
Thank you for the help, everyone!