Dastardly said:
You'd probably be happier if you cheated every now and again - just know when to say "when."
I have the line of "single player=cheat as much as you like". I used to buy games that even when 'learning' were difficult. Either they were needlessly complex or I was playing like I had ten thumbs all moving as one but the game itself had a rather intriguing story.
Blood Omen: Legacy of Kain had some truly difficult and complex mechanics. There was armours to find, weapons to gather, blood pools to drink from to increase your health but it was a huge game and the travelling was arduous even when you got the various form powers to quick-fly to certain spots or run really fast as a werewolf. But the story had me hooked from even a brief rental of the game: a young nobleman, murdered on his travels and turned into a creature of the night to seek revenge only he gets drawn into the magi-political happenings of the Circle of Nine, guardians of the land who've been tainted after the wife of one member, who we later find was the old Guardian of Balance, had been murdered in her sleep and the madness had spread to the others and corrupted the land. So Kain's revenge trip suddenly becomes a quest to save the world while understanding his new place in it. Then he finds that he is the new Guardian of Balance and has to choose his fate once he has restored the pillars. Had I not cheated I would've given up after the first dungeon because it really was a lesson in pain and frustration.
Then there's Saints Row 2 where cheating to give unlimited ammo, health, etc helped overcome my ten-thumbedness and allowed me to progress through each of the campaigns and finish the story. Being an invincible supercriminal was pretty much the mindset that you're going for in this game. Sure, I may have missed the challenge of getting there but it was suitably long and the story was engaging enough to keep me interested not to mention the costume creator which made repeated runthroughs different. My first run was with a suitably dark-skinned beauty who carried and authority to her walk and the second was with my cockney rogue who sported a goatee (as close to how I looked at the time) and just really brought his own madness to the fray. While the story was the same for both, the way they came out was different enough to keep it fresh.
And there was Guardian Heroes on the Saturn which a friend and I used to play way back and we'd activate the debug menu to play the multiplayer and single-player, making use of all the characters to fight (we once had a six-man tramp beatup that lasted hours because they were all level 99 and did pathetic damage to each other). We had limited time to play together so it was a time-saver and allowed us to finish the campaign in a few nights. Well I say finish because it was my first experience with branching story paths. At the end of each mission there was often choices you could make which would change the path that you took and even the ending you got to see.
These days my time is even more limited so cheating in single-player to get to the end is often preferable or it's justified because I get to experience the ending of the game first-hand rather than through someone's journal or a video on Youtube. Although I cheat less because the games are designed more to the home audience with checkpoints, difficulty settings, control adjustment menus or trying something different with the way a 'game' is supposed to play like with Portal where you never actually shoot anything except portals.
Not that I don't still cheat but it can sometimes help validate a purchase.