Scratch

Change X instead of Y to make people move up and down.

Just make animations to make people look like they're dying. Here's how you do it:
Make as many costumes as you want the animation to be long.
Put this script in where the people are dying:

[if <touching [bullet]>]
     [repeat (10) ] <---- or the number of dying costumes
        [next costume]
        [wait 0.04 secs] <---- You can change the 0.04 to whatever you want if you want the animation to go faster or slower.