Up: That’s a mighty large robot you got there. Sadly, your “assembly” mechanic needs retooling. As is, skipping your untap step isn’t great, but that ability only costs 3 mana, and you’re probably using it on turn 7. Combine that with all the new proliferating from War of the Spark (and the originals from Scars of Mirrodin) and you have a hexproof Blightsteel Colossus that gains you 24 life on turn 7. I like the idea, but this execution is too powerful.
Unholy Collusion Sorcery Exile all creatures. If you control a Bolas Planeswalker, an Eldrazi creature, and a colored artifact as you cast ~, you win the game instead. There they stood, Bolas, Eldrazi, Phyrexians...never before had the multiverse seen such a terrifying alliance.
Up: I'm no expert on Magic yet, so don't quote me on this, but it looks to be about on par with other alternate win cards. It seems to make thematic sense too, from what I understand about Bolas. (I'm not going to give it a score, because again, no expert on Magic so I don't know if this card is actually good or not.)