Thanks for the feedback, it really helps me when people find things in my game that I don't anticipate.
To start off, the mute button is just a place holder for now, I plan to get that fixed as soon as possible.
The problem you had while sliding down a wall and getting pushed to the side has to do with the ability to place walls on yourself which I will get rid of in an update.
As for the 2nd problem you had, what exactly do you mean. If you clicked outside the flash game it would place a block? Or did you click and then drag your cursor, then placing blocks outside of the game? I tried it right now and I couldn't recreate clicking and placing blocks outside of the game. It could have something to do with my computer, but if you could get back to me that would be great!
And thanks for the ideas, I do plan to make the way to the objective more obvious those last two levels I know are very difficult to get through. I do plan on later adding different types of blocks as well to spice the gameplay up a bit.
Once again thanks for the feedback.