If you execute the code shown in the README it should run an experiment against the MNIST dataset[0]. If it performs as well as other deep learning examples[1][2] you should see a test error rate of less than 1% on classification of handwritten digits. This is pretty impressive, especially considering the fact that the collection contains a few digits that I cannot even recognize myself.
[0] http://yann.lecun.com/exdb/mnist/
[1] http://deeplearning.net/tutorial/lenet.html#lenet
[2] http://neuralnetworksanddeeplearning.com/chap1.html