Being such an efficient creature that can hit the battlefield on turn one, this can quickly get out of hand by creating 1/1 Cat creature tokens whenever it connects with an opponent (triggering life gain)
The Metagame Since Explorer is proto-Pioneer, the early metagame can be defined by whats good in Pioneer
The most obvious of these factors is the synergy of haste with Saproling Burst, which was known to some as "The Fix." That extra turn almost doubled the strength of the Burst and made it hit for the full 20 damage in only two turns, which would normally mean a kill on turn five, or turn four if backed up by a Blastoderm
"Borderless card art allows the art to be more immersive and front and center," said Cynthia
Stealing something like an opponents commander or combo piece can absolutely shut down their game plan, though you have to be careful since it is an aggressively unfun strategy
Other Formats There are also a host of other formats either supported by Wizards of the Coast or made by the players themselves