Reward given for anyone who finds the name

Now I have been searching for this movie close to 6 years now and it’s always eluded me.

I watched it when in primary school on a film day so this would have been early 2000s but the movie was already out and known so I’d say it was released sometime in the 90s.

I only remember certain scenes vividly as it was a while ago since I saw it, 10years to be exact.

So these kids/teenagers go into a graffiti wall to find several magic keys that open a box, in that box is a pathway to another realm.

The grandad gets captured by an evil queen and is locked in a electricity cell.

There’s a scene where the kids/teenagers are having a snowball fight with monsters/allies of the queen.

In the end they lock the queen away and save their grandad.

Now the monsters were in costumes so there wasn’t any cgi going on in the film, well little to none.