everything aggro, if you cannot pull the combo off in time. Forerunner can clear for you with the hatchling early game if they just spread, but most times if you dont get early removal you just lose.
i lost mostly to being a new player and not knowing when to play to my outs, i think for playing at my LGS the guys kinda took it easy on me when it came to the priority of spells and helped my with interactions. I think if there was a way for me to grind games i could master the deck, and win even without the combo.
I believe against good serious players, aggro will be a hard match up. I did not play against any control heavy match ups, like the dood playing 4 Tetzimocs and 12 removal, but im sure i would have no idea how to play against that guys deck, and complete the combo. I think it would have to be something where i sideboard
Bloodlust Inciter and wait for a turn where i could dump the combo with a lucky stick of
Forerunner of the Empire.
not 100% sure if thats correct, but its fun either way