Activision was the first third-party Atari 2600 developer, but they didn't have to reverse-engineer the system from scratch -- they were all defectors from Atari. They did invent plenty of nifty tricks, though.

One podcast talks about Imagic, another VCS third-party developer: One guy, Bruce Pederson, was amazing. Without any documentation whatsoever, he attached an in-circuit emulator to a VCS and reversed the entire video architecture - including the special registers that doubled or tripled the sprites along with the requisite code timing issues. Took him two days to do it.

Parker Brothers used existing carts to inform their efforts: The 2600’s zany graphics chip was the key thing there. My first contribution was to write a disassembler for already-published cartridges. When analysis of the circuitry presented ideas for how the sprites and background worked, I wrote small test programs on the 2600 to verify our assumptions. With these combined efforts, we figured out how everything worked in a few months.

[1] http://2600gamebygamepodcast.blogspot.com/2014/02/q-with-ima... [2] http://www.retrogamer.net/retro_games80/the-making-of-star-w...

Not the same, but I still remember reverse engineering Game Genie hex codes for Battletoads to warp to different levels or get powerups.

Growing up with an NES my religious parents (at the time) would be very wary of what games they would purchase for me. There was a Christian bookstore that would sell unlicensed Widsom Tree [0] Christian games and they were all kinds of jank, had distinct cardridge shapes and colors [1], and in most cases, had very little Biblical accuracy.

[0] https://en.wikipedia.org/wiki/Wisdom_Tree [1] http://static.giantbomb.com/uploads/original/0/2538/290022-b...

I had a very religious mother, and we lived with our pastor. I remember having something like a dungeons and dragons board game I owned burned in the backyard because it was 'devilish.' However, the pastor had no problem himself playing his own copy of Castlevania 3 on the NES and letting us watch. Sort of a tangent, your comment reminded of this experience though..

Review of Super 3D Noah's Ark, including quite a bit of history of Wisdom Tree:

https://www.youtube.com/watch?v=7FKEg2__57c

And if you want a reproduction cart: http://www.wisdomtreegames.com/store.html#!/Super-Noahs-Ark-...

I'm hoping they're not destroying original carts to create this, though.

Ha, biblical accuracy. Good one.

Fantastic. Sachen are another "well known" bootlegger of cartridges. I first encountered their gameboy carts, but they did NES too (which are now $300+ on eBay!)

Edit: is the site broken, or is the author blocking archive.org?

Author here. Sorry about that, the site went down unexpectedly. Back up again.