There aren't many games that a 2D (Saturn in this case) controller would be useful for, but there are a few - a couple of 2/2.5D platformers and fighting games. Anyway, I had no idea if this would actually work - I gathered some info/pictures that described how the N64 controller board can be cut, but didn't see the end-result.
Here's how it went:
This is what's left of the N64 board:
....with the Saturn (PC) controller board:
Current button configuration is:
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