Mythical Detective Loki Ragnarok

Loki must go into a virtual reality game to save his friends that are stuck inside. The game taps into the player's subconscious and uses the people close to them. Enemies in the game are destroyed by destroying the red jewel that they wear. In the end a monster from the world of the Gods is in control. Loki defeats it and they are back to reality. (Source: Wikipedia)