Thanks for confirming! That's Edge's stricter default security (tracking prevention + SmartScreen) blocking the file download inside itch's embedded frame. Just use Firefox or Chrome.
Thanks so much, really glad you're enjoying it! A C64 version isn't in the cards right now. it'd be a pretty big undertaking since the graphics, sound, and memory setup are totally different from the NES, even though we'd get a leg up from sharing the 6502 CPU.
