OOOOHHH! Now I get the boomerang. I think selecting attack and after that right-clicking would make a bit more sence, but this is good as well. About the tutorial: I tought that you hadn't had the time, and the fact that you can re-open it later is really helpful.
About the smaller room: I think that only the starting rectangular room could be a bit smaller, or it should have had more enemies in it, because I didn't go to 80% of that room. The other rooms were okay.