There are a number of Sideboard cards to consider if Blightsteel Colossus is giving you trouble. Path to Exile, Revoke Existence, Fiend Hunter, Faith's Fetters, and the list goes on. Also maybe utilizing some of the effects that don't allow creatures to enter play from the library such as Grafdigger's Cage

Combo Polymorphist's Jest with something akin to Pyroclasm.

This is a really fun concept, two minor issues. Your win condition seems to be getting Blightsteel in the graveyard and using gruesome encore to kill 'em. However, reading the text on Blightsteel, if it is put into the graveyard, it instead gets shuffled into it's owners library... I also think your control/zoo matchup is pretty poor, so I might add some board wipes (anger of the gods/damnation). You could also finish off your curve with some super friends.

i heard Vapor Snag has some giggles at Blightsteel Colossus

Two words: Kasmina's Transmutation . Even better frog!