Thanks guys! Really appreciated.

I think I'm going to do a second run with a proper soldermask. The board is functional but can use a few updates, mainly some pullups on the control lines of the AVR side of the RAM and a "write-protect" jumper for those who want to be certain that the games aren't being modified in a competitive setting.

I'll have to gauge demand but it's kind of intensive (need to desolder a DIP package without ripping up any pads), which probably isn't for everybody.   Not sure if I'd be up to coding support for more than a few games so I'd have to release a pretty good manual on how to develop for it, also dual port RAM is expensive ($12 for that chip!).

The possibilities are more or less endless. Batsly, you're a monster! Is this going to see general availability in any form?

You could sell a ton of these if someone wrote some code to make this friendly for speedrunners!!!

Damn. You've done it again! This is seriously excellent work.

Finally finished the new NES project I've been working on. A RAM replacement for the console that allows you read/write any memory location live via serial. You use your actual games in the console, they don't require any modification to run. The board also provides additional features like a remote reset / frame stepping for debugging.

Here is an example of the stuff you can do with it - pulling live data from Blades of Steel to create a scoreboard / trigger a relay on a goal.
https://vine.co/v/M6WzFBXeX1e
https://vine.co/v/M6WZlFjdJ69

http://www.batslyadams.com for technical details / more examples.

Also : yes it would make a great interface for a synth because of the bandwidth involved, it just wouldn't be very practical since you need to make a pretty major modification to the console. Having a cart is still the best way to go.