Yeah they were proper mental, pretty sure they were put in for the lols by rare.
I assume you guys are referring to Perfect Dark Zero, the 360 version? I don't remember the n64 version to be particulary difficult, even on dark agent.
Anyways, an average dark agent bot match for you guys who have never played: http://www.youtube.com/watch?v=jg6lVpodhq8
The player actually does a decent job but he was playing on the biggest map. Playing on a smaller map was nearly impossible.
edit: On a side note, I think PDZ was extremely underrated, and it's a shame it never made it big. It plays differently than any other shooter I've played to date. The campaign is fun for those who want a
very challenging single player experience and enjoy stealth-shooters. Weapons are unique and all have specific roles and uses, sounds are great, visuals are great for the time (character models svck in my opinion though, too cartoonish). Also it used trueskill rankings (like halo 3) for the online portion of multiplayer so if it was ever popular it deffinitely would've attracted a competitve crowd.