This release dramatically improves error messages using clojure.spec. You don't need to do anything to enable it -- debug mode is automatically enabled if :optimizations are set to :none. In particular, the attributes map for each entity now have specs, so if you try setting an attribute to the wrong type, or neglect to provide a required attribute, you'll see a nice error message now. Try it out in the interactive docs.

For example, try changing the :animation entity to no longer provide a :duration attribute. Or try changing the :shape entity to provide an odd number of :points. You now get spec errors, instead of silent failures. If you want to disable debugging even during development, just pass {:debug? false} to the last argument of create-game.