I checked for any scratches or anything like that, but at the same time I'm no expert at all.Instead of adding additional new replies, please consider making an edit to your last post if no one has replied.
What sort of checking did you do that led you to that conclusion?
The 3DS has very limited internal memory and bad things can happen if you start trying to mess with it. Why not just buy the cartridge?
If you downloaded this game from some random Internet site and this is the only game that is giving you problems, then it is not impossible that you downloaded a bad copy.
The game is Phoenix Wright Ace Attorney Trilogy which only had a physical release in Japan. I also tried other games such as Terraria and Shovel Knight which also didn't work too well.