I tried this a while back but got constantly annoyed by the little things that kept on piling up making me stop.
I don't know if it was left out or missing in the translation I read but was it ever eventually explained how he got there? Later on he just whipped out this time traveling device without any foreshadowing, explanation or what not like we were supposed to be familiar already with it.
It annoyed me that the important McGuffin that started the whole mess & he kept using constantly reminded me that anything about it was never explained for so long.
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