I’ve been thinking about this for a long time and I haven’t seen any horror games that I know of use this.
Is this, in any way possible to make in roblox? 
This system looks like it could work very well for this use-case!
You could insert a SpotLight into the player’s head facing forward, and lock the camera to first person. You would most likely need to wait for phase 3 of future is bright for higher resolution lighting as seen by the screenshots.
I would advise caution, the creator of the system mentions that it is not suitable for production game environments. Game performance may be harmed on lower end devices and phones.
The only problem with this is that it would not give that full flashlight feel. By that I mean the dark inner rings in the light.
Well of course you should take that into account, it does say that on the post. I just posted a solution that I think could work out.
Those games use a shadowmap based flashlight (which is why the light also has a texture). This will probably become possible with the 3rd release of FIB.
If I remember correctly, BillboardGuis with a white image kinda fade out shadows behind it and could be used to achieve this effect pretty well.
