nerfed informal

In particular, in the case of items or abilities which have been nerfed players can become upset over the perceived wasted efforts in their obtaining the now nerfed features.

So much so, in fact, that in the period I was playing, there were calls for Mysterious Challenger to be "nerfed" ie reduced in power, to ensure an even playing field.

While a game's developers may not consider these tactics to be outright exploitation of the underlying game engine, often these tactics are 'nerfed' in some way in order to discourage twinking, such as removing, repositioning, or reducing the effectiveness of certain items within the game to make the progression more linear between players.