The 2D side scrolling Teenage Mutant Ninja Turtles game from 1989 is arguably the most difficult game to have ever been released for the NES.  While many fans of the TMNT series may be fond of this game the chances are that about 10 percent of them have actually completed the game in its entirety.  

While it would be cool to have the NES TMNT game on the Nintendo Switch eShop there may not be too many people who would actually buy the game given its notorious reputation for being a very hard game to beat.  Also, if the 1989 NES Ninja Turtles game is ever to be featured on the Nintendo Switch eShop it should be less than $8 for the game itself opposed to Mario Bros.