Hey does it happen after a few mintues of inactivity? As in - you leave the game and go to make some coffee or surf the internets?

Completed.

I still don't know what causes the error - but using a skill (RMB + mouse wheel up) seems to resolve it.
I will although keep looking to fix it.

Goblins.... well I was lazy to implement AI to avoid pits for them. Let's say they are so fast that quicksand doesn't affects them or something ;p

Your equation is quite wrong. Let me correct that.
No donations = no time to work on game

Unless you find me people who have enough knowledge to make something more complex than agario and want to work for free.

Well I have implemented initial idea for quicksand. Which may not be what you had in mind.

Could you describe how making a party should look ike?

Ahoy mate I am working on mage currently.
I am not switching to pay once model yet tho.