Does your country celebrate Halloween?

German here.
The country doesn't celebrate it, at least not like it's done in the US. Depending on the state All Hallows Day or the day before is a holiday, but apart from churches not many people really "celebrate" them.
But some people like to use the day off to have a US-inspired Halloween party. And some children also dress up and go from door to door. But this varies from family to family. Some streets might be swarming with kids while the next street over nobody knows that anything is going on. So many houses aren't even prepared to give out candies, they often scramble to get something to give out.
But about two weeks later there is the St Martin's feast. Although that's also dependend on the region I think overall it's more common. It consists of several parts that vary from region to region. But in all regions children carry (usually self made) lanterns. Then they either march through the town while singing songs, ending at a big fire and usually a guy on a horse dressed like a Roman soldier, representing St Martin. Or they go from door to door in small groups, sing songs and get candy. Often it's both on separate days of the week.

Here in Hungary it's an excuse to have a party while dressed up. It's not a huge thing with trick or treating like in the US.
- Even in the USA trick or treating can be a regional thing. Where I grew up in NJ we always trick or treated. When I moved to MD last year I bought candy expecting kids to trick or treat in my neighborhood but no one ever knocked on the door.

We will see!
Traditionally it's been a day for young people to go out partying and clubbing in costumes.
But last year 67 people were crushed to death and we had an official week-long period of mourning. We will see how Halloween is treated this year.
- Wow that looks bad. Crowd crushes can happen at any large event like concerts or festivals. A few happened in the USA recently. As it always is, in this case it was a planning issue, more people showed up then expected and there were barely any police to respond once things went south. I'm sure it'll dampen this year's events but the incident isn't necessary because of halloween.

In Finland, we go trick-or-treating during Easter. Traditionally kids would dress up as witches, but these days you're more likely to get a visit from Batman.
Halloween is basically not celebrated at all, though some bars may hold a theme night. Not on the actual date, but like the closest weekend. Students will also use it as a theme for one of their parties.

The media has been pushing it in the last decade here(Japan). But it's more like putting on cat ears and witch hats and taking pics for instagram. Trick or treating is not common unless somebody in your neighborhood organizes an event.