It rotates the other way.
Yeah, right.
You CANNOT put a flywheel on backwards. It's not physically possible to mate the flywheel with the crankshaft unless it is the correct direction.
I have seen some that would go in backwards But 99% of them will not set flat on the fly-wheel if it is backwards. The clutch disk will hit the fly-wheel bolts if not installed right.
It will tell you it can not read the discc
It is impossible for any bird to fly directly backwards. Unless the wings were put on backwards it wont work, as the wings are designed to propel forward.
You have to remove the transmission to do this.
You cannot physically put a clutch disk in backwards unless you force it together. If you do this you will destroy the clutch disc and possibly other clutch components.
pcv valve wont work properly
You could have blown fuses, melted wiring or damaged computers.
When you connect the battery backwards you can cause major damage. You can blow the alternator or its fusible link. You can destroy electronics, particularly the various computers - and these are not cheap.
If it is up on a hoist, rear wheel drive will do that. The differential determines which wheel gets preferential power.
the mothballs will fly away
Rotors can only go in correctly one way and will usually snap in place. If you manage to put one in backwards the car will not start and it will likely tear up the cap and rotor.
Most of the time you cannot put these on backwards because the filters normally have a big end and a small end. Most are labeled in and out. But if this happens, the car will not run correctly when it is started because it will not have enough gas.