How to make DooM-like Glory Kills in a Player to an NPC?

The question says it all.

I'm making a game where it will have tons of enemies, it's in First Person and has weapon systems, I want to make a Glory Kill system in the like (Just like in the DooM games).

I suppose it will need this stuff:

*Both (NPC and Player) be animated with an animator from Roblox Studio. (I can do this, don't worry, I know how to animate a character in Roblox)

*Something that blocks the keyboard keys until the animation ends, so the Player cannot move until the end of the Glory Kill.

*The necessary scripts to doing this (I honestly don't know how to insert an Animation to a Player so then he does it) :((

*Some conditions like, "If an enemy's health is below 25%, there is an 85% of probabilities that the enemy will make a Dizzy Animation and will glow in an neon orange "aura", which in that time lapse any Player can do a Glory Kill"

*In the time lapse where a Player Glory-kills an NPC, both cannot receive damage until the animation ends (because a Player may be killed while doing the animation, as well as the NPC).

*The Glory Kill gives health to the Player who did it.

I think that is everything, I know it seems to be very difficult, but I've just started in the Roblox Studio so I want to use its full potential.

Thank you so much :)

At a certain health, add a selection box and enable the UIS with range, making it play 2 animations, one for the player and one for the player dying, making it play the animation, once the animation finished, the player dies.

if Hum.Health == 15 then
	local SelectArm1 = Instance.new("SelectionBox")
	local SelectArm2 = Instance.new("SelectionBox")
	local SelectLeg1 = Instance.new("SelectionBox")
	local SelectLeg2 = Instance.new("SelectionBox")

	SelectArm1.Parent = Char:FindFirstChild("Left Arm")
	SelectArm2.Parent = Char:FindFirstChild("Right Arm")
	SelectLeg1.Parent = Char:FindFirstChild("Left Leg")
	SelectLeg2.Parent = Char:FindFirstChild("Left Leg")
	-- and the userinputservice code enabling it
end)

To give the player health just get the value of the player who killed and give them health with humanoid