I only did everything in order to get all the achievements. I honestly find 3 to be a far better game, i havent played 2 yet. Some complain that 3 is easier, which i will agree with, but not because 1 has harder enemies or anything like that, it is just that 3 has far better and more refined mechanics. For the most part when i died in 1 it was due to something wonky going on like the camera being weird or slipping off of something stupid. Very rarely did i ever die from an enemy. In contrast to 3 where most of my deaths were from me not being skilled enough to actually fight a boss. Basically to me the difference ends up being, in 3 almost every death 100% feels like your fault, you are more angry with yourself than the game when you die. In 1 the majority of deaths were due to either bad mechanics or bad terrain/level design, which makes you far more angry at the game itself, and doesnt feel like it is you yourself that needs to get better, you just need to figure out the trick or get lucky, nothing to really do with skill.