Hello! Spoilers below:
The breakdown is just for the poem, for flavor not necessarily understanding the endings other than one specific reference. Basically the story is: you are the shadow of a vampire who has forgotten everything because you strayed too far from the body out in the woods.
There are two endings, both which end in the shadow, "you", is destroyed. You can either choose to live one last day as yourself and die in the sun, or you can choose to free the vampire and become them again. The cat wants you to become the vampire again and gets annoyed when you decide you'd rather be yourself, but hints that another shadow, or version of you will take your place.
The basic theme of the story is, should you be who you want to be even though you'll end up destroyed, or should you be who someone else wants you to be, which will destroy you anyway. There's no real happy ending here.
Sorry it's confusing, it's a lot more vague than I had intended, but I'm glad you liked it!! ♥