The stone blocking the Krotite armor cave resets back to its original place when I return with the armor, so I get stuck inside (can't drag the stone out of the way from the inside). And looking at other posts no-one else is experiencing this? The armor doesn't seem to be of any importance, so I can skip it I think, but this is still a bug.
Some other (but not all) such stones seem to be resetting as well, but with them at least I've not got stuck (no need to enter another map on the other side of them, yet).
And I have version 1.03 or some such of Aquaria. Experienced this with the demo as well, I think.