Your concepts are all good, but your tense tends to slip all over the place which is distracting. For an example, the opening line of [013], "smiling" should be "smiled". [009] also gets a bit repetative with its word choice ("These were the days where the days"), but that habit drops out in the later ones, so I think you've conquored it.

Your imagery is very good. Riku's pale skin, the snapping of bones, the spray on Riku's face are all very vivid without getting wordy. I think if you ran these pieces past a beta reader, they could go from "good" to "marvelous" quite easily. You clearly have the skill.