@stuartlangridge If you want to try out every level without having to pass through everyone, you may use the Konami Kode (Up Up Down Down Left RIght Left Right B A). It will unlock a level selector. Also, there is no sound made by the ' "fire dots into the air" triangles'. I think what you're talking about is the SlowMo Sound not perfectly looping which creates a small variation in the sound which can be misunderstood.