This little launcher does work alright, but you need to find a very specific sized (consistently about 8-9mm diameter) and shaped (round) treats or kibble to put in it for it to work smoothly. If the treats are not the right size they will jam/misfire/split. Usually this means you just try to shoot a couple times more to clear the jam, and it works again, but it would be much better with the proper sized ammunition.
As far as the dog is concerned, the treats ping out quite fast so if the dog isn't ready or used to the launcher they'll just miss where the treat is going. Get the dog to back up a bit and shoot only when you have their attention and it goes much better. Overall though, not bad and it does what it's meant to do.