After much of the deaths were even taken with jokes, Oowada's execution comes off as a punch in a gut for a gag series like this. Seriously, even Ishimaru's Catchphrase takes a sad turn:
Hell, Fujisaki's death was also very sad. Just the way that he tells Oowada that he'll be accepted for who he is is heartbreaking and adorable... and then Oowada lifts the dumbbell-and it just cuts to the portrait of the dead Fujisaki. It's horrible.
Episode 5
"Man. This really is not welcome in a school environment." in the stinger upon Ishimaru's death. A farewell to the character most viewers would associate Faulerro's voice acting with.
It's also quite sad to see how much Oowada's death affects Ishimaru, especially as he sits staring off into space at breakfast, not responding when he hears his name or the claim that someone's running in the halls, and when he believes that Oowada's murder victim is still alive on the Internet, showing how much he's having difficulty accepting that his friend killed someone and was executed for it.
Other
Faulerro's Tumblr often has extra content. One, posted after episode four, showed Ishimaru's browsing history secrets. Most have to do with being on time and school environments, but the very last entry is him searching on Google "HOW DO I MAKE FRIENDS". Hits even harder considering he makes a friend that episode who dies. And then does himself in the next episode.
By the time DR3 Side Future Abridged happens, our Naegi is almost completely cynical. It matches up with his line of thinking in the original DR3, but it's an even worse case here— every line he says is dripping with sarcasm, and he admitted to Chisa that he expected for things to go down the toilet once he finally found something or someone to believe in. And it does, with him being forced into another killing game, and Chisa already dead.
. Most have to do with being on time and school environments, but the very last entry is him searching on Google "HOW DO I MAKE FRIENDS". Hits even harder considering he makes a friend that episode who dies. And then does himself in the next episode.