Prepare to see how broken the mechanics are. I went through that right off the bat. Luckily it's only the dollar Bill machines you can't use (weapon and plasmid machines are ok).
The game feels much better on the lower settings, but it's basically just a shooting galley romp there. In 1999 mode, its just cheap with glaring problems in weapons balance and AI.
The castle protect part? Funny enough I found that super easy and beat it in one try on 1999 mode.
Is there a framerate unlock option on the PS3 version? I own the game on the 360 and found that using that mode made the controls MUCH more responsive on my second playthrough. Might help out with the combat a bit as I felt it did. The game also never chugged the framerate like it did when I played through the first time with the option off.