The core thing with higher difficulties is that dying really just sends you back to checkpoints without taking away resources or progress. Those brutal modes like give me no mercy and give me god of war definitely make enemies hit harder and take more damage to kill, but that's where the extra challenge mostly ends. During tough boss battles, you'll still get checkpoints so you won't lose too much progress, though they might be a bit more spread out on the hardest setting.

Something worth noting is that while enemies become real damage sponges on higher difficulties, the game keeps things fair by not adding extra penalties when you die. The real challenge comes from mastering the combat itself, since those beefed-up enemies will definitely test your patience and skill. If things get too frustrating, you can always drop the difficulty down, just remember that once you lower it from give me god of war, there's no going back up to that level.