First, the two planeswalkers from my set. You can guess who they might be...
In the Mega Man world, Dr. Light and Dr. Wily are two opposing forces, smashing against each other in a constant struggle for supremacy. Dr. Wily is more aggressive, and undermines his opponents. Dr. Light is all about preservation and building. While both ultimates are blowouts, I wanted Wily's to require one fewer loyalty counter, to play upon his aggressiveness.
Truth be told, neither of them is particularly groundbreaking. I didn't really have any special ideas for how to approach them, so I basically just made fairly strong planeswalkers with effects that fit the colors I decided for them. So if you say they're pretty vanilla, I won't be offended.
Two of the rare lands from the set also play off of Wily and Light. I feel really good about the mirrored flavor text, and I think the two effects are similarly powerful. I'd probably rather have the Fortress, but in the right circumstance, and if there are a lot of bomby artifacts in your deck, Light's Lab could be a real win.
So, now you've got five cards from my custom set. What do you think so far? Comments welcome.