Halloween or Hallowe'en (a contraction of "All Hallows' evening"), also known as Allhalloween, All Hallows' Eve, or All Saints' Eve, is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. It begins the observance of Allhallowtide, the time in the liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed. - Wikipedia
As you can see from the definition above, Halloween was a normal, healthy observance in the Church which has over time become an instrument of Satanism to bring young minds into captivity.
"It's just fun and pretending" is often cited as justification for delving into the Occult. And, in most cases, where children are exposed to the Truth, there is no observable permanent harm.
However, as exposure to the Truth has waned in our Society, so also has exposure to the Occult increased. This cannot be a healthy turn of events.
In the Occult observance of Halloween we effectively have created a holiday honoring Satan. Now that can't be a good thing.
When you look at world history you see that in Pagan countries all their holidays honored the Occult and in so doing worshipped Satan.
We are fast heading in the direction of Paganism as all of our holidays are being commercialized and associated with ideas completely devoid of the Knowledge and Worship of God.
How is it that Israel fell so quickly into Paganism when Moses was in Mount Sanai? Exo 32:1-6
When people are not in Fellowship with God they will seek fellowship with the Enemy of God - Satan. It cannot be avoided.
So, while there is a great industry built toward commercializing Halloween and most modern parents simply try to entertain and appease their children, it is important that we recognize that there is nothing good about the current Halloween observance. It is Evil and Destructive.