Contest #1: PlaneShaper

Your prisoner-card is a cool concept. A creature that can be kept under control with force. This looks like a good way of showing prisoners being kept under magical control. is a good way of showing the alignment of colors in your story, which is something I always appreciate.

The guard-card strikes me as odd. I don't really understand the story it is trying to tell. The flavor text helps, but isn't enough to carry the rest of the card. I'm guesssin the idea is that this is the spirit of a former prisoner who possesses others. But I don't think it's a good fit on the guard-side.

Mechanically, I think Suppression Simulacrum is very interesting, but I really don't get the flavor. Black-Cell Forgemaster, on the other hand, is a simple way of showing prison shivs, although the flavor text does most of the heavy lifting. This would be a great common showing simple aspects of prison life.

The first card doesn't do justice to the prison I described, in my opinion. As a criticism on a prison system, it kinda works thanks to the flavor text, but as a spell used on a prison-plane it falls flat. I also don't really see how the ability and the flavor interact, but this could be a failing on my part. Veteran Guard's mana ability isn't a bad way of showing increases in experience, but the rest of the card doesn't work all that well. Exiling creatures who die doesn't really work as a way of showing guarding. Mana abilities aren't generally put on Black or White creatures and there are other ways to show increases in experience that work better with these colors.

I don't see why Ogre Rioters can't be a single Ogre. The plural is mostly unnecessary. Anyway, this card mostly stands or falls with it's ability word. I think Breakout is a cool way of showing riots and the ability word could go in pretty much every color. SO that's cool. For it to show up on a lot of cards (which this ability wants to do) would hinder the worldbuilding a bit, because it would make riots feel a lot more frequent than they actually happen.

Iron Restraints similarly hinges on the interestingness of the new ability. Equip for enemy creatures is something a lot of people would like to work with and this is the simplest way to make it work. The ability on the artifact is a bit bland but stills fits perfectly within the setting. I actually really like it.

The prisoner card tells a good story. It is a little bit funny that the Serial Killer can only kill one person, whereas actual serial killers generally need a couple more victims. But that's a small price to pay for this card. This actually sets up a lot more cards that do something similar: showing the criminals and then showing them as prisoners. It would be cool to see a lot more of that. (Maybe I'll make a thread about it.)
Your guard is also interesting. A prison in Magic: The Gathering would obviously have guards that would hinder the magical abilities of the prisoners. This is a good and powerful way of showing that part of the setting. The card is relatively powerful, but would make for a good rare.

Your first could would probably need flavor text to really work, but I can see the logic behind it. While normal prisoners would just get a cell, more powerful ones would be magically subdued. I can see Suspend working in this regard. The wording "if X isn't 0," is an odd variant on "X can't be 0," but I see no reason why it shouldn't work.
As for your second card, this is how I'm interpreting it: the card represents guards checking up on a cell, so the prisoner needs to stop with his shenanigans for a while. Like above, this card probably needs flavor text to really work on an intuitive level. I also don't think suspending other player's creatures and Detain would really work within the same world.

I understand what you're shooting for with the Duelist, but I don't think it quite works. I guess this could work with proper art, but even then it would need a name-change. The abilities on the card do work as a way of showing how prison guards try to take every advantage they can get. Provoke is the sore thumb, since no guard with respect for his own safety or that of his colleagues would deliberately provoke someone. But the card needs it to work, so I'm willing to overlook it.
The second card is a very mechanical card and I think there are better ways to present shankings. If we were making a set, though, this card could very well get in.

Panoptican Prison is an ambitious name. Conveying most of the concept of a panopticon on a single card is going to be hard. You took a stab at it and I think you did a good job. It's not perfect, but since it's about as hard as designing a card called "Representative Democracy" that covers all the proper nuances, so I'm still glad to see what you did. The first part on the card is an abstraction of being able to see more, I take it. That's probably the most important thing this card would need so good to see it. The activated ability looks like guards holding down a prisoner. Not exactly needed for a panopticon, but it doesn't hinder the card and still fits within the setting.

And another shiv. Shivs seem to really capture the imagination, but then again prison creativity is interesting to think about. The card is a little basic and maybe even a little underpowered. The flavor text is what makes it work, together with the name.

Your prisoner seems to be more of an active criminal. Or a sadistic guard. This really doesn't feel like a prisoner.

Your guard feels right, though. It's one of the simplest designs, but that doesn't make it bad. I really like it.

Tevish Szat, for making a prisoner with a story behind him and for really thinking about the implications of a magical prison.

Honorable mentions:
Phoenix Toph, for making an actual panopticon.
Confused, for making a guard that could serve as the main forces of the prison.