It's fair to say that most gamers expect two things out of an epic video game boss fight: a high level of difficulty and a suitably prolonged length.
There's a lot to be said for a challenging boss fight that tests the player's mettle, and often, this will lead to battles that take far longer than just about anyone expected.
We've all been there: a boss has trounced us for hours on end with its absurdly powerful attacks, and only after wasting an indecent amount of time chipping away were we able to finally break through and win the day.
These 10 boss fights aren't all necessarily the most brutally difficult gaming has had to offer - though many of them certainly are - but they all absolutely took their sweet time for players to beat.
Whether offering up a phenomenal level of challenge or simply forcing players into a relentless endurance trial, these bosses generally took hours to defeat, after which you were likely left wondering what other, more productive activities you could've done with your time instead.
Still, that feeling of accomplishment, of all that invested time finally paying off, absolutely speaks for itself...