Yet another jam game for the NES/Famicom, this time a Sokoban-like puzzle.
Move crystals and altars around. Whenever the number of crystals around an altar changes, summoning circles will activate, creating doppelgangers who mimic your every move. Each type of circle requires an specific number of crystals, part of the puzzle is to figure it out.
You can press the “B” button (or whatever it’s bound to on your keyboard, probably the “Z” key) to undo movements. Or press “Start” (“Enter” ?) to quit to level selection.
Relevant link: https://wendelscardua.itch.io/doppel-effect
File download: