Gave it another go. The different expressions are a nice touch, though I think the number of deaths requires should probably be different for hard and easy mode - you've got a lot more time to die over and over on a difficult part in easy mode, after all.
I actually got the alternate version on the score screen; The game seems to give you a weird score screen when you beat easy mode with 250+ deaths; I seem to always get one of these poses, rather than the regular win screen. I don't think it's related to whether you've entered the code.
I haven't tested the 500-750 range, but 750+ seems to work as normal.
Also I finally noticed the display glitching out on the floor after 12 to avoid displaying an unlucky number. That's a cute touch.