At this point it is too early to tell if cartridges will be available for purchase after the Kickstarter campaign completes, but I hope that this will be a viable option, and will try to make it happen.
Backers will have the option to receive the game as a limited edition white cartridge, instead of the standard grey version. This will only be available to Kickstarter backers.
I do not plan to make any significant change to the game itself after release, but to acknowledge those backers who are collectors I will try to make a visible but insignificant change to the ROM used after release to differentiate post-Kickstarter cartridges from those given to backers. Most likely this will be a version marking on the info screen.