These are the features i have worked on.
This mirror was in combination with a pumpkin powerup, which basically was a zombie blood halloween edition. If you grabbed the powerup the mirror would turn into a portal, you could see the pack a punch on the other side of it.
Once you jumped into the mirror you got teleported to the pack a punch and open the gate from within so others could access it freely now.
I also wanted to replace the hellhounds with something different, we ended up using the Cryptids from Call of Duty: Ghosts. Since i always like to put in a personal touch, i gave them the ability to teleport. This happens when they receive a certain amount of damage and then teleport away to attack from a different location.