It was heavily used in Extended and was an automatic hit at every casual table format in which it was legal
Still, a powerful and flavorful card that rewards clever sequencing and sneaky plays
Whenever you attack, you investigate and find a Clue
As for Modern, Infernal Reckoning targets basically come down to three decks: Affinity (where Infernal Reckoning kills everything), Eldrazi (where Infernal Reckoning kills between everything and most things, depending on the specific build), and Hollow One (where Infernal Reckoning only kills Hollow One itself), although it does pick off the random creature finishers from traditional Tron decks like Ulamog, the Ceaseless Hunger and Wurmcoil Engine along with KCI combo pieces like Scrap Trawler and Myr Retriever as well
In the early game, it applies solid pressure
You can still play the app as usual up until the shutdown