Because, up til that point, it had remained around the same level of difficulty. Then, in the very last area of the game, it becomes incredibly easy.
Games with huge difficulty spikes
Lincoln James
Ian Scott
...
Julian Lopez
...
Cooper Harris
everytime
Thomas Allen
...
Dylan Nguyen
Any S.T.A.L.K.E.R. game ever
Kevin Mitchell
Breakdown for Original Xbox.
The White Gauntlet was just fucking rape.
Carson Lopez
I only really agree if you think the game drops after the start. I never really had any trouble with STALKER games after I got some gear.
Colton Foster
nethack
Juan Morris
The difficulty spike happens multiple times, but the biggest is floors 23-30