Hmm. I don't remember any typing errors though I playtested the game a lot of times :D. The sound icon glitches but functions perfectly to my experience. By invisible walls, I assume you're talking about the level before the final level where platforms are made out of individual blocks instead of rectangles (this was made because the level was designed in a computer in which the project wasn't installed and then reedited once opened in the main computer.) We improved while we made the game, so the level design slowly improved with every level xD