What keeps me coming back is it honestly just feels fun. Like said before, it isn't amazing, and it is definitely quite cheesy at times. But I think it knows what it is, embraces it, and just has fun. Sometimes the episodes fail in what they are trying to do, but in general it is just a lot of fun...
Long and short of it is, I guess, it's like playing RE5, not an amazing game, but pretty good. Super cheesy at moments, but a hell of a lot of fun...