The best part about this is the fact that the +1/+1 counters effectively have haste since you can put them on old creatures and attack with them the same turn
The most depressing part of facing down Doran may be the other three copies of him waiting in the enemy's deck, which due to his legendary status may be stuck in his hand at this very moment
In the case of Gifts Given, it uses cards from your opponent's library, whereas Gifts Ungiven uses cards from your own
Cards like Spectral Procession and Battle Screech feel like they were custom-made for this deck due to their efficiency, and Hanged Executioner gives you some utility at a slightly higher rate
Kiki-Jiki, Mirror Breaker [The Infinite Loop Engine] Kiki-Jiki, Mirror Breaker has been enabling absurd board states for years
Go find that unbeatable creature and put it to work