Okay, I was wondering just what the version differences were, and here are my results:
There was one change: Missile does less damage in the English version.
All other abilities do the same amount of damage, and all bosses have the same HP, weaknesses and resistences.
I updated my earlier post, and cleaned it up a little.
The current run does not ever attack anything with Missile that has enough HP to make a difference. So I don't see any reason why any follow-up movie shouldn't use the English version. Perhaps there are other version differences (less lag, etc.), but unless a new run actually attacks bosses or tough enemies with Missile (unlikely), the claim that attacks are stronger isn't valid.
Of course, two heads are better than one. If anyone else could verify my results, I'd be grateful.
On a side note, reducing Missile's strength was a stupid move. If anything, they should have made it stronger.
It's by-far the lowest-tier ability, at least for fighting bosses. I've soloed the arena (unassisted) with every ability except for that one.
The ability should have been this game's Ball ability: hard to use, but insanely powerful to make up for it. It's really too bad, as I otherwise really like this move.