The thing that fucks the game is the save system. Its either the challange of the game and anger and frustration creep up on you so you save after every little progress, before every enemy, or you go doom mode losing hours of progress. Absolutelly no inbetween.
You either cheat yourself out of the experience by saving ultrafrequently and loading after every little screw up, or you play doom mode and play ultra, ultra safe, without any experimentation.
I tried to make myself only safe at the beggining of a mission for example, which makes you play carefuly and going with and trying to fix mistakes(for example being spotted in stealth missions), but still allows you to try reasonable things as the loss of time in case of failure isnt too big. Still though, you need plenty of discipline to not break the rule.
You either cheat yourself out of the experience by saving ultrafrequently and loading after every little screw up, or you play doom mode and play ultra, ultra safe, without any experimentation.
I tried to make myself only safe at the beggining of a mission for example, which makes you play carefuly and going with and trying to fix mistakes(for example being spotted in stealth missions), but still allows you to try reasonable things as the loss of time in case of failure isnt too big. Still though, you need plenty of discipline to not break the rule.