I just witnessed a glitch on level 3s a crowd, when when forward jumping with the arrow at the beginning I just kept running right and I ran through the level and finally got myself doing some wierd stuff at the end of the roof. Oh, also It made my game lag and I had to refresh.
When you use all your weights, just before the menu appears, you can click and hold and if you hold it too much and release it, the weight will hit the ground and the menu will disappear, freezing the game.
For people wondering how to get the spyglass, you can't find any, just aim with the rifle in the dark and suprisingly a flashlight will appear on your rifle and reveal the shadows.