All gun games get boring fast. It's just the nature of the game. They are pretty to look at, and sound effects on some games like Haunted House can add to the overall game interest. But ultimately, they are repetitive and get old quickly. Not that that stops me from buying one every so often, but I only buy when I can get them cheap, knowing I will want to sell them before too long.
Another factor in buying gun games today is that some lib types don't like guns in general and this carries over to shooting galleries, making them a bit harder to sell. Also, I have seen that many of today's kids don't know how to properly aim a rifle, I guess because their father/grandfather never took them out shooting. They tend to play rifle games like Call of Duty, pulling the trigger as fast as they can without really aiming. And then tell you that the gun isn't accurate. Usually, I will then play a game, hit 10 or 15 targets in a row, and just smile! They look at me like I'm some kind of genius. LOL!