Unlock the secrets of Barcelona's Gracia via a real-life riddle game

I bought the game for my husband's birthday, as he loves a good history-related riddle/ scavenger hunt. We found the clues to be a nice mix of challenging and easy; and we liked the tidbits of history you are given along the way! A few things for the creators of the clues: 1.) It's very hard to see the sides of the buildings at night, so I would recommend people play during daylight hours for visibility reasons. 2.) At least one of the clues was outdated, since businesses tend to move or go out of business (esp. on Travessera de Gracia). Also a building had been recently painted so the clue was painted over! (We used Google maps history street view to see the older version of the building in order to figure out the "subtract top from bottom" clue). 3.) My husband's one critic was that the "scrambled" letters/"backwards" words clues were too evident, and it would be more fun to have to figure out the words through a different kind of riddle. Perhaps some sort of key you receive when you download the game? I was pleasantly surprised at how good the game was overall and would recommend it to friends who are visiting.