Episode 4 already out? Yeah really, grab it here.
There are people in the world who accept the word "henshin" in their subtitles due to its exposure in US media (primarily Viewtiful Joe, a relatively niche game) and some of the other Rider things before they were 90% kisama yatsu tachi. This episode gives a good reason not to accept it though: Mana asks Shouichi about how he transformed. If the subs were using Henshin, the options at this point would be for her to ask about how he "henshined" or to be inconsistent, neither of which is a good idea.
This episode also has much more of Shouichi's stupid sense of humor, and it sadly doesn't translate very well. They're pretty much invented from whole cloth here to get the basic idea of what was happening without relying on spelling out the Japanese language gags he was using. Because, after all, the only Japanese you should see is in the release is the group name, and we're sorry about that.