Leagues are where you just play five matches on your own schedule and get prizes based on your record. You can ignore the start/end dates... that's basically just when the leaderboard resets I believe. It's always running.
Challenges and playoffs are actual tournaments, one of which happens every Saturday. Challenges are open, playoffs you qualify for through challenges and leagues. Playoffs then qualify you for an annual championship tournament, iirc.
@stormanimagus I don't think we disagree by that much really. You're talking about this working as one more disruption piece in a full suite of already-good disruption cards, and I agree with that. I'm only saying that it's not a total haymaker that shuts certain decks out all by itself. It's a strong effect, but it needs to be immediately followed by either a massive threat or additional disruption.
I mostly agree with @volrathxp's take on Deafening Silence. It's a good card but not backbreaking, and I'd actually say it's weaker than Thalia or something like that against storm decks, because it doesn't give you a cumulative effect that protects your disruption pieces. Still worth using but you definitely have to avoid falling into the trap of "oh I'll play this and they're just boned."
Uh wait I mean it's unbeatable and we definitely need Necro unrestricted to combat it.
Tinker blightsteel is an option for DPS. A hatebear deck that runs multiples of this card would tend to be less threatening than the usual hatebear decks.
I'm not sure how helpful that is, really. If you're on the draw (which is where this printing really hurts), Tinker still needs a turn to set up, during which they will likely play a sphere, rod, Containment Priest, etc. It seems nicer to me to just try to remove it although that's easier said than done too.