Robert Seddon told us that in Retro Gamer magazine #51, p. 39, they talked about a removed 4 players coop mode that was meant to be in Contra 4 for the DS. Matt Bozon, director of the game, told to RG that “Our first playable incarnation was four-player Wi-Fi, but it was taking us in the direction of a wildly unbalanced game with fewer bells and whistles. We dabbled with Rumble Pak, but the team wanted each feature done right or not at all.” In the magazine we can ever read that some screens of the 4 players mode were released online, but i dont remember any.. do you know where to find these?
In a related note, on Wikipedia there are some infos on the leaked Contra 4 Beta ROM: “A Prototype version of the game was leaked to the internet in ROM image form. The NDS header indicates a US serial, but the game has been suggested to be a European prototype. The similarities between the prototype game and early game trailers confirm that they are the same. Among the many differences from the final product, each level starts the player with 99 lives, the player can choose any level, the Factory and Alien Hive stages are incomplete and sounds are missing and/or placed in different cues.”