One of the first games I've played where I genuinely want to know how the designers pulled it off - to see "under the hood", if you will. Nothing short of meticulously designed, the game at first feels somewhat forbidding, especially the bosses, until you realise that every action you take gets you closer to reaching the end goal.

Was I getting better, or were the earlier bosses tuned to become slightly easier after a certain number of runs?

This game gave me one of the most satisfying feelings of progression, where I inched closer to the end goal each run. Somewhat Dark Soulsian, after your first few runs you swear that the wall is just too damn high, but then the game plays so smoothly and strengthens you so subtly, that by the time you reach the wall again, you find that you've already smashed through it.

Also the writing rules and the art design is...cough....godly.