Nobody spend 5 days into a single riddle. There are parts of the Citadel to explore without finding the 2 riddles. I did exploring in parallel until I found the riddle 2. It's perhaps possible to finish the game without to solve it but it won't be easy.
Once I found the riddle 2 I explored more and found more problems to solve some nice tricks. It's quite clear that it's important to find this riddle 2 but for riddle 1 I think there's no solution or it's not that important to find it.
It's also clear that those 2 riddles aren't well done but also it's even more clear that now many players play games with one eye on the game and another eye on the walkthrough, that make them quite lazy and used to get feed like little birds.