It's all in the details. (Unless you're adding pictures, that is.) Are you planning on describing each death in detail? Blood, guts, the whole works of gore? Because, if you've noticed, in movies, you can show people dying in kids films all the time--you just can't be graphic about their deaths, or if you are, you can't show them. There are cartoons that have gore, but it has to be played for laughs and brief, without getting too disgusting.
If you're just going to tell me "somebody died" that's not even PG worthy. If you're going to go into painstaking detail over someone being eviscerated, you need to be careful not to push too far into X-rated because we only go up to R here. (Same goes for sexual stuff. Kissing is NBD. A little innuendo only deserves a PG. A sex scene is an R. A graphic, thoroughly detailed sex scene doesn't belong here.)