Sorry , that is a bug.
We have fixed it in newest version (0.4.1).
Sharks won't attack rafts untils walls on its way have been destroyed.
Thank you for reply
Rly cool Idea and nice game!
When its finished and @ Steam?
Can i preorder?
Have a nice day!
The exact time to go to Steam has not been decided yet.
We will continue adding stuffs before that.
Thanks. Have a nice play! :D