yeah i know the night guard gameplay was scrapped but i played it using the code and here's some ideas on how to fix it

1 the door controls

the door controls are stupid and the open and close buttons should be put toghether so instead of pressing e to close the right door and c to open it you would just press e to close it and press e again to reopen it

2 changing up the mechanics of freddy, foxy, bonnie and chica

so some changes to make the mechanics more original would help, so basically chica and bonnie would only move in a set path and would not kill you if you walked up to them and they would try to get to your office and mess with the breakers causing the power to be shut downpreve tthis with the doors

Foxy would stay in his pirate cove and be slowed down by the cameras like usual but when he bangs the door he takes more power then usual so you have to go to his cove and put your flashlight on him to reset him fully

Freddy would free roam around and would not have a set path but would rather try searching around for you, if he spots you he will keep chasing you until you flash him in the flash with your flashlight or you block him with your door

Golden freddy would apear in a random part of the building and you would have to find him on the minimap and put your flashlight on him or else he would start draining the power and rasing your awareness casuing freddy to come after you

Shadow freddy: he will sometimes apear near you turn of your flashlight or your awareness will be raised

Springtrap: he will sit in the back room and will stay in there most of the time but some times he comes out and when he does keep your noise low or he will attack you

and finnaly

the puppet: he sits in the back of your office wind up his box every once in a while or he will destroy your doors

the flashlight

so basically your ability is a flashlight you can turn it off and on using the left mouse click when it's on you can see and use it on some animatronics though some will require you to turn it off

and i think that's how you could implement the guard mode