If you received this letter, well then, consider yourself special. I killed myself, and these letters, well, these letters are all that's left inside from me. If you received this letter, then, I'm sorry.
Dear Family, Friends, and Ponies,
When you receive this huge package, look at the back of it. There's a list. Find your name, find the number next to your name, reach for the envelope with your number, and read the letter inside your envelope. You can only read your letter. Don't read one that isn't yours. After you've read it, put it back. You can't keep it. Then pass the package on to the next pony on the list. The last pony should and will burn the entire package. Because I'll be dead by then, so my words should be dead too. I hope you'll abide by these rules. Consider it my last wish.
I'm sorry,
A dead Sparkle
This is just way too blunt. Think about how someone who's suicidal would feel and how they would say it. You don't get a prologue in a suicide note. It either goes right in to the reasons why or "If you're reading this, I'm already dead. You probably have a lot of questions. First, know that I love you and that I'm sorry. It's not your fault." etc.
Also, what's the point of this passing game? Who'd make a game out of a suicide note? You may be tempted to say "Pinkie," in which case you wrote about the wrong pony, and still no. It feels more like you're trying to cover up the plot hole created by the whole story not just being told in one letter rather than thinking realistically about how it would have been written.
Again, who in the world would write this?