Something I ran into playing a Japanese game that isn't widely explained. Katakana can sometimes be used for emphasis on words it wouldn't normally be used to spell, kind of how we could put them in caps or cursive.
My last Encounter was オレ and ヒミツ
Ore and himitsu, me and secret. At the point where you know the words and can read it doesn't throw you off, it's just something i had to learn that wasn't taught.