The app was good before. Had some small issues not registering some sets but was working well got building sets. Now for the past few weeks the app doesn't load at all. I contacted customer service and I'm just waiting for a fix now. Pretty rubbish when an issue like this just stops you from building the sets. I'd love to see Lego make these apps optional in future and include proper paper instructions in the sets. I don't want to pay for more Lego Mario sets as things are.