Halloween Merge is a mystery-themed merge game that features supernatural elements. After a young woman named Chloe finds and wears a family heirloom, she's transported to a strange world where magic and the supernatural exist. The player attempts to help her navigate her familial responsibilities with the hope of escaping this world and returning to her own. They can only assist her by completing merge and renovation tasks.
Chloe learns that her family's magical manor desperately needs a makeover. Yet, she doesn't have the tools, energy or money to perform each task. The player generates items from toolboxes. They then merge the items to create new ones. Items include cleaning supplies, gardening tools and seeds, magical dust and potions, raw and whole building materials, and decorations.
After the player uses an item to complete part of the renovation, they receive stars, coins, energy, and additional items. They sometimes also receive gemstones and gift boxes as rewards.
Halloween Merge provides the player with several side quests. For example, Chloe's aunt has disappeared from the area. The player must help Chloe find the family's spellbook to search for clues about her aunt. The game eventually unlocks a village stage that continues the story and merge play as well.
