Rockman Dash 2 (not psx!)

[Roll Dash]

At the Nino ruins (Japanese version, though I'm guessing it's the same for the English language release) as soon as you activate the underwater feature the game completely glitches out and becomes unplayable. Since this isn't an optional dungeon there's no way to proceed past this point, which is only about halfway through the game. I've attached a screenshot of the effect; maps and status menus are fine, but everything else ripples and warps.

Any ideas/progress on how to handle this, or is it something that's just not fixable at this point in time?