The visuals were actually pretty good but some of the sounds were fucking terrible. Specifically anything that isn't already "pre-rendered", like the sound of a monster shuffling, Jill moving, etc. The bottom screen was also pretty GBA-ish looking. I don't usually like to bash things, but this stuff bothered me.
I beat Sif on my first try. Just stay under the belly the whole time. It's actually not that hard. As for getting to Sif, when you walk to the open forest area with the invisible enemies stick to the left and you'll only have to fight the knight and the bandit.