How To Get Your Game Onto an NES Cartridge
Not that we recommend trying to learn Assembly and creating your own 8-bit freak-out, but here's how Party Time! Hexcellent! gets it done:
1) Start with a blank text document.
2) Type in all your code from scratch.
3) Input the code on a compact flash drive.
4) Put the drive in a special development cartridge for Nintendo and see how it works.
5) Oh, it doesn't work right or at all? Tweak your code.
6) Repeat (a lot).
If you don't have the development cartridge then you'll need a soldering iron, because you will be pulling 28-pin EPROMs (memory chips – you might recognize them as those black rectangles or squares with the silver legs you see inside computers and such) and putting them back in. Oh yeah, you need an EPROM programmer as well. Hope you know how to use one of those. We recommend you spring for the dev cart.