The heli components are hard to find, apparently its intentional as well lol. Also there are some spots that you can get sandwiched really easily in as well.
When you know where everything is it gets eazier, but it's very hard solo and it's eazy to get surounded and killed. And if you decide to do easter egg, you always have 2 zombies to worry about. I hope their mext map will have all perks buyable without easter eggs.
@Thatcheeser there are multiple. There is chopper escape ending, Snowfella bossfight to unlock PaP (not counting Jerome since he spawns regularly) and blizzard nade build-able if they count,