Salvager of Ruin

The restriction is the entire design: the target has to have hit the graveyard from the battlefield this turn, which makes this a save button with a hard window rather than a recursion engine. It exists to turn a one-for-one trade into a wash. The sequencing is the tricky part and easy to misplay: the ability needs a legal target before it can do anything, so the permanent must already sit in the graveyard when you sacrifice the construct. You cannot activate this in the middle of a targeted kill spell to blank it; the correct line is reactive on a delay: let the opponent's removal resolve, then break the 2/1 to pull the dead permanent back to hand before the turn ends and the window closes. That same requirement is why it offers no defense against a board sweeper: a wrath kills the construct alongside everything else, so it dies before it can be activated, and if you crack it in anticipation, your other creatures have not yet died to be targeted. The "this turn" clause forecloses any graveyard toolboxing: you cannot dredge an old threat back, only recover something that just left play. As a colorless piece it slots into any deck willing to run a fragile body as insurance against a specific answer it expects to eat. The cost is that it spends its own body to do the work, so each rescue is a one-shot: once the construct is gone, so is the safety net.