Big flying dragons are usually great in Limited, but the only thing Twinflame Tyrant asks of players is sufficient investment into red and maybe another creature or two to be a slam-dunk pick
You've also got a few sources of life gain (see Mask of Griselbrand, Basilisk Collar, and Blood Artist), and a few ways to wipe the board if things get out of hand (see Decree of Pain and Blasphemous Act)
They stay locked and unreadable all the way through the competition - so not even we know which numbers hold an instant win
The only other options are Aquitect's Will, which just puts a flood counter on a land (and draws you a card if you control a Merfolk), and The Flood of Mars, which can transform creatures into copies of itself if you opt to put a flood counter on a creature
These have been appearing more and more in recent Magic sets, to the point where Im surprised they dont just keyword this as the peek keyword ability or something like that
Zur becomes killer when you animate high MV enchanments that you can cast for cheap, like Overlord of the Hauntwoods and Leyline Binding