Sonic 3D Blast has a special place in my heart. one summer in elementary school my buddy and I were in the basement taking turns playing this game, and we'd just got the furthest we'd ever gotten, to some stage we hadn't ever seen before. my younger siblings were running around the basement and my sister tripped on the controller cord, yanking the Genesis forward, causing the game to crash. we were stunned—Sonic 3D Blast is pretty difficult, especially for a couple of kids, and it had taken meticulous effort to get as far as we did. we were about to lambast my sister for her carelessness, causing us to lose hours of progress (the original game has no save system), when suddenly the TV flickered and a blue screen exclaimed:

         C O N G R A T U L A T I O N S
    YOU HAVE FOUND THE SECRET LEVEL SELECT
                    SCREEN

there was much rejoicing, and we proceeded to check out all the levels we had never been able to get to, including the final boss. I never knew how it happened until years later I read something about how jiggling the cartridge can cause that to happen, which still seemed like black magic. it wasn't until even later that I found out, from the youtube channel of the guy who worked on the game and later this romhack, it was because the error interrupts (exception handlers) restart the game and jump to this congratulations message and level select screen: https://www.youtube.com/watch?v=i9bkKw32dGw