I spent almost the whole movie with that question in my mind although at the end it seems like all that monsters collection they had down below were real supernatural entitiesNot to mention the ancient GodsYet, the zombies were activated by pressing a button.
The zombies weren't activated by pressing the buttonRemember when the lead girl and the pot-head find the opening which leads to an elevator, which in turns takes them into the massive collection of cubes? When the bunker guys press the button, it moves the cube housing the zombies to the opening, where they climb outThe idea is that all the monsters in the film are real, having been provided by The Ancient Ones for the ritual, and are housed in the cubes until selected.
paint something on the pebbles,use grass and small stones for decorating photo frames.
