Scratch

Try making a code (for your character) that says something like...

when gf clicked
if <(health)=[0]>
end

In this example your message will be restart.

broadcast [restart]
stop script
when i receive [restart]

In this case your start screen is called b1.
Below is the stage script for recieving restart.

when i receive [restart]
change to background [b1]

Say you have a creepy death scream for your primary character? Use that on the stage if primary character dies.
Your character's reaction... (you can put the sound here instead it'll work better)

when i receive [restart]
hide
play sound [example freaky screech]

Now for enemy death. Do the same thing except don't change backgrounds and use a diff sound.  Maybe make it change to a pool of blood costume then a dot costume (dot of the smallest size on the painter, you can see one in this script when the guy and rock disappear -> http://scratch.mit.edu/projects/eveadelekitty/2963896 )
and he'll look like he's dying if you use this block right

wait [1] secs

Eve, you forgot to wrap your first if in a forever loop. Lemme put it all in one script;

when gf clicked
forever if <not <(health) > [0]>>
 set [health v] to [0]
 die script //Usually a hide block and a broadcast to end the game
end