I can look in to the size thing, but how exactly do you round an angle to the nearest pixel?
I think it just comes down to the way the canvas is resized/stretched. It seems C2 isn't drawing the images and then scaling them up; it's scaling up the images and then drawing them. I don't know how else to put it lol.
Here's a visual comparison:
<img src="https://dl.dropbox.com/u/105711543/Images/example.png" border="0" />
The bottom row is what you'd expect in-game Megaman to look like at 1x,2x, and 4x at a 45? angle. No matter how big he gets, he appears exactly the same as he does at 1x resolution. That's good.
The top row is what Megaman looks like in C2 - That's not an angled Megaman scaled up, that's a scaled up Megaman at an angle. He's completely re-drawn in a different resolution!
(I know NES Megaman or any 8-bit sprite for that matter wouldn't be scaled or rotated - it was just a cleaner example. There are lots of 16 & 32-bit games with sprite rotation & scaling and the same thing applies.)