Who? the only one hard to understand is pendulum and it's not really necessary in the game right now. At most you still just need to read the cards. Mind you there's a lot more of them now but it's still the same concept as the original.
Yugioh isn't that complex. People are exaggerating. There's not that many types. There's normal, effect, magic, trap, fusion, ritual, and synchro. Not too convoluted. Still waiting for them to release the Egyptian God Cards hope theyre good.
This shit was obviously always going to be a bad end because it was completely out of character for Shirou to refuse to join (if only to end the war and the suffering it was causing as quick as possible), though admittedly I wasn't prepared for quite how brutal this one was going to be when I first watched it.
It was also just stupid given that he was twice attacked before he even had a Servant and was officially part of the war, so what kind of dumbassery possessed him to think no one would attack him if he gave up? I mean Shirou isn't the brightest tool in the shed but he isn't THAT dumb (it wasn't him who almost walked straight into Medea's trap, Bad End notwithstanding).