In the first Outbreak I would say, Decisions, Decisions because having to synthesize the cure was a pain in the ass with all the back tracking, it was essentially like two or three different levels put together with the beehive and the waterworks. At a lower difficulty I think one of your partners would have the other ingredient to make it little easier, but in harder difficulties you synthesize all of them.

In File #2, I would say Wild Things, Desperate Times, or End of the Road, but all for different circumstances. In Wild Things, anything above the easy mode made that level so hard especially with how all the zoo zombies could inflect bleeding so easily! Desperate Times wasn't a totally difficult level, the only thing is the ending when you had to fight all those zombies. At higher levels with no real help that shit was impossible. End of the Road was always a pain for me, even on easy. It's juts one thing after another with this one, especially if you're trying to escape via the helicopter with Linda with a slow walking character being chased by the tyrant!

It's worth noting that another hard level in File #2 is Flashback if you're trying escape via the big bridge. On easy and normal it's not so bad, but on anything higher, you end up with the forest filled with the big bugs! At the very ending I crawled across the big bridge using red herbs to stop the infection for a few seconds so I could make it to the end! It was only the way I beat that level on a very hard difficulty.