The release of Excitebike on the Nintendo 3DS eShop was an important milestone for the company's struggling portable. It marked the beginning of the "3D Classics" line, a series of games that would feature older classics remade with 3D effects. However, since Excitebike we haven't heard much about Nintendo's efforts -- until now. But don't get your hopes up. The way things are sounding, the 3D Classics series is being approached as a limited set of games.

In a recent Iwata Asks interview, which was hosted before the eShop was launched in early June, Nintendo had only targeted six titles for the 3D treatment, including Excitebike and Xevious. The interview didn't shed any light on the remaining four titles. Though no reason is specifically given for the small scope, the challenges of development may have curtailed Nintendo's original plans.In a discussion with Nintendo president Satoru Iwata, 3DS software planner Takao Nakano noted that simply applying 3D effects to older games is far more challenging than even Nintendo anticipated. When Nintendo attempted to port Namco Bandai game Xevious, they discovered making the game's ship appear to float in the air had unintended consequences on gameplay.Suddenly the timing of attacks was off, as was the game's animation. The original developers had never intended for players to detect the transition of attacks between the ship and the ground below in this top-down shooter, so adding a 3D effect changed everything. Nakano told Iwata that the result was a game that took almost 20 times the original intended development time.Despite that, the game was completed. That doesn't mean other titles were avoided or cancelled though. Nakano mentioned that Tennis for the NES was considered, but applying the 3D effect to a game that already simulated it wasn't very impressive. If that wasn't enough, actually hitting the tennis ball with the 3D turned on proved challenging. "It took as much work as making a tennis game from scratch... we had to conclude that the resultant value would not be worth our hard work, so we scrapped it," Nakano concluded.