Getting rid of the skeleton in your closet can be either a breeze or one tough uphill struggle, though, depending on the format
All told this is a mediocre card quality spell and a good card advantage card resulting in a very good card overall
Armageddon should be used carefully when you can press and advantage already on board, or if you think you can draw out of it faster than the opponent
Also, despite the fact that many decks run Swiftfoot Boots instead of Lightning Greaves or together the Boots cost just 1.25 here for the cheapest version and the Greaves are a pricey 5.99 for the cheapest again, that's a big number difference
Until end of turn, your life total can't change, and permanents you control gain hexproof and indestructible
The beginning of combat step happens every turn, even if there are no creatures on the battlefield that could attack