It's way harder than PES4, the diference is really impressive. You've to pay attention to tactics and strategies a lot more than in previous PES, it really feels like real football.
Konami has done things right this time, i get bored of PES4 in three months beacuse of the "arcade" style they applied, now the defense and the midfield controled by the CPU are so strong! They keep perfectly their position and play really great, Konami has done a great job with the IA.
I used to trash every single team in PES4 with teams like Español or Spartak Moscow, now after 15-20 matches i've get about 10 draws, 4 wins and 3-4 defeats, just scored about 7-8 goals. It makes the game absolutely brilliant. I know it gets some time to get used to every new PES but this time i feel like the difficulty will remain months and months not just like PES4.
The great thing; I get mad when i score it makes me jump from the chair and scream goooooooooooal! That's what i expect from PES.
I'm loving PES5.