Finland. Traditionally not a thing at all but each year the commercial aspects creep in more and earlier. Nothing about them can be contextualized further than "it's an American thing".
Lol, it’s a big, big deal. Bonfires, dress up, trick or treat was all done as kids. It’s a bit different to tv version in America, but that has crept in over time. However, it’s always been a big deal as a festival.
Food is different - monkey nuts, barn brack (sweet bread) with a fainne (ring), cloth or coin to predict the future. The púca. Fireworks. Bonfires. Public holiday. School half term. Change of seasons.
Not a big thing in Poland but it's present. Kids have fun going around their neigbourhood after dark (smaller ones usually under their parents' watch) hunting for candies, young-to-middle-age people get an excuse to throw a party. It's mostly a curiosity, not something people wait the whole year for or go out of their way to decorate their house like in the US. I personally don't enjoy dress-ups but if kids are having fun and the religious people are getting triggered because of a "western, non traditional, pagan custom", then I'm all for it.
UK - not really. less than half the houses in my area put up any decorations/leave out a pumpkin for it. though might be because I'm in an area with a lot of old people.
I'd say far less than half based on my experience - I've very rarely seen people putting out a pumpkin or other Halloween decorations in their houses.
The one aspect of Halloween celebrations that I think does exist in the UK is trick-or-treating, which I did do as a kid, but even then it's been probably over a decade since I last had a trick-or-treater knock on my door, though that may be partly a London factor.
In (Madrid, at least) Spain, it's a sorta huge deal in schools, with every kid under 14-15 dressing up, a lot of schools doing costume parades, and many classes giving out candy and watching movies. But outside of school, it's all but ignored. You'll see little kids in costumes and a few bar events, but no trick or treating and no decorations.
The much bigger day/event is carnival, for which kids wear costumes again and there's a big parade in most cities.
In Norway and it's definitely becoming more of a thing. Growing up I never did it, but now I run out of lollies because there's so many kids out and about.
On the flip side, Norway does have their own Halloween style celebration where you go around dressed up and demand lollies from people door to door (julebukk - I'm not sure what the exact date for it is, and I think it varies depending on where you are, but it takes place between boxing day and up to and on new year's Eve) which I've definitely noticed has been declining the last few years. Maybe kids want to celebrate Halloween more than julebukk? Probably because on Halloween you can just, show up and demand shit while on julebukk you actually have to prepare a little song and whatnot.
Shame because like, julebukk is a) actually traditional and b) has some weird ass lore behind it. Like it's something about appeasing the Christmas goat (who may or may not be a demon saint Nicholas personally went down to hell to beat the shit out of until he agreed to help him)
They think it's an anti-christian holiday, and thanks to recent revisionism, they now think christianity was first practiced by Magyars, thus Halloween=anti-Magyarism.
Not a big thing here in Sweden either, although shops do their best to promote it. It gets a little mixed up with "Allahelgona" (all saints day) which is close. Halloween is on the 31st of Oct iirc, and Allahelgonahelgen is on the first Saturday after the 31st of Oct.
On allahelgona you're supposed to remember your dead, so a lot of people visit graveyards and put our candles. It's usually very beautiful.
Scotland has a thing called guising, which is like trick or treat but without the trick. You're supposed to tell a joke or do something entertaining in exchange for the treat. Don't live there anymore so no idea how much of a thing it is anymore.
From the US so it's obviously big there, though it isn't quite what it was when I was a kid in the 80s and 90s.
Live in the Netherlands now and it's not much of a thing outside of the occasional bar deciding to make a thing out of it or maybe North American immigrants throwing a party.
growing up in former eastern germany we had sankt martin's day (11. nov) as "laternchen" (small latern). it involves kids going door to door and singing songs in exchange for candy.
when halloween started appearing it was too close in date and too similar but seen as "worse" since the "trick or treat" thing seems more bratty lol