He was called out on all his shit, accepted his mistakes, and has since not only mellowed out, but also been nothing other than a good friend to the MC.
The problem with this is that in the most recent update it is made clear that he's always looked down on MC as basically a useless, idiotic loser. He's not a good friend, he's just an egoistic prick who enjoys having MC around to make himself look better. Maybe I'm being too harsh, but as I mention toward the bottom of this post, Deryl treating MC as a rival comes across more as cruel than friendly.
His traps are pretty basic, and he has had months to prepare them.
I'm sorry, but that's just an excuse for lazy writing and plot armor. No matter what, the author was just going to write that Deryl had planned for that outcome and had whatever traps he needed to win. That's not clever or interesting, in large part because we are just watching the author respond to his own actions by saying that, off camera and without us being informed, one of the characters had pre-planned to defeat whatever the author had the other character do.
But, it also is just lazy handwaving and does require near magical levels of competence. Have you ever actually tried to lay a mechanical trap? For them all to be effective, not only do they have to work perfectly, the MC has to be in the right place at the right time and not react. What if the MC had simply confronted Deryl in a different place? The real answer is that it wouldn't matter, Deryl would have months to boobytrap any place he ever went to, which is my point. And, the MC doesn't have to be genius. But he is written as an idiot in his confrontation with Deryl in order to make Deryl look better. The competence even from MC's fight with Jake (eyes in the back of his head, dodging plasma bolts, removing his ears) minutes earlier is just gone. He just stands there and gets doused in oil instead of dodging for literally no reason. Etc.
Not only is Jake's imprint on Deryl a failure, but he also loses interest in maintaining it.
I'd be happy to be proven wrong, but I'm willing to bet that Jake's suggestion to the MC (if the MC kills Jake) to protect Mia will be something the MC can't shake off no matter what, while the complete mind rape of Deryl is something he can shrug off during your fight.
You'll probably get the option to eat him, especially if you're on the Corruption route.
I seriously doubt it. We are supposed to like Deryl.
The author set up three story elements and I just don't think he realized they didn't work together.
1. Deryl is awesome. He's a genius with unstoppable will who can do anything he puts his mind to and is hung like a horse (not to belabor this point, but he's basically the same size as the MC after he alters his body). This is done in order to let Deryl be useful after MC becomes a superhuman, but once Deryl becomes superhuman it becomes nuts and the author went off the deep end with it.
2. MC is pathetic. He's short, weak, pining after girls he can't have because he's also ugly and has a small penis (again, this is something one of his romantic interests tells him outright after he changes his body). He's dumb and a loser on essentially every dimension before he gets powers. This is done to make his transformation more interesting/the differences more stark (and to explain why the character usually doesn't do anything clever with his powers).
3. Deryl and MC are rivals. This is done to give them a healthy sense of male bonding, camaraderie and drive to outcompete each other.
The problem is that 1, 2 and 3 together just don't fit. A guy like Deryl who hung around a guy like MC and acted the way Deryl did would be both a terrible person and a terrible friend. He doesn't seem to be friends with MC after the most recent update so much as enjoy being better than him and having someone around to make Deryl shine more.
Anyway, I'm done venting. If you still like Deryl, more power to you. I just wanted a sanity check on my own opinion.