When working with loaded images and canvas on your local file system, some browsers will throw security errors. This may occur when using SpriteSheetUtils or getObjectsUnderPoint, and lead to a number of other repeating errors. To avoid this, test on a web server (a local web server should work fine), or test with a browser that doesn't throw these errors (Safari seems to work). If you have python installed on your system you can enable a simple web server that's fine for local testing by navigating to the directory where your project resides typing the following at your command line: python -m SimpleHTTPServer Your project is now available at: http://localhost:8000/