For me, the greatest thing about the C64 and the European computer scene is the immeasurable abundance of creativity and technical prowess that was cultivated within that community. The C64 was like a little box of wonders, you acquired new games and programs by recording sound, pressed each and every one of the keys with weird runes to see what happens, you typed these ancient spells to draw a circle on a screen or make sounds come out of it and there was this feeling as a kid that there was this weird, alchemic quality to the computer. It came out in an interesting time where computers were still more for the enthusiast, tinkerer and DIY, radio club and engineer crowd, but it introduced that DIY mentality to a lot of youngsters, which led to the proliferation of great, creative programmer minds, most evident in the demoscene community, but also seeping into every corner of the games industry.
Its legacy is that same creative spirit that shows its influence today in a lot of UK, Nordic, European and even to an extent US developers in general. There's this interesting mix of experimental, creative ideas and technical knowledge, that try to push the industry forward, often with varying degrees of success, but that's what being a pioneer is all about. It's interesting when you try to look at some of these studios and games today, like Little Big Planet, Wipeout, Battlefield, Driveclub, Alan Wake, Wolfenstein: TNO, Donkey Kong Country (and trying to push new ideas with Sea of Thieves), Starfox and the Super FX chip, Grow Home, No Man's Sky and many others, there's often this distinct thread of creative thinking that feels a bit distinct and different from a lot of what you see as mainstream influences. There are a lot of unsung heroes and influential people that have created ripples in the industry but aren't nearly as mentioned as often as a lot of the Japanese juggernauts. To be fair, I have nothing against the Japanese masterminds that created some of the most influential games and hardware ever, it's just that it would be very beneficial and healthy for the industry to rediscover its other influences and always strive to find new, fresh ideas to propel games forward.
Can't say that most C64 games have stood the test of time, but the legacy that little computer (and its brethren and successors) has left on the world should be recognized and celebrated.
Happy anniversary, C64.