One of the things that has remained constant is the design on the back of Magic: The Gathering cards for obvious reasons, namely that you need to ensure that no matter what set a Magic card is from, it should be completely indistinguishable from any other card in a deck
Laser-Focused on Noncreature Spells Unlike the catch-all Force of Will, Negation specifically counters only non-creature spells - instants, sorceries, enchantments, and planeswalkers
How do you play targeted discard
These games could have gone a little better, but the person who cracks the artifact aggro code in Explorer/Pioneer will be well rewarded because there's a ton of potential in the archetype!
If the creature can't attack any of those players but could otherwise attack, it must attack a planeswalker an opponent controls, a battle an opponent protects, or a player who goaded it