Showdown is a "crowd-pleasing, hard-scrapping Autobot" who "built his celebrity hammering 'Cons in the Kaon fight pits back in the dark days on Cybertron." He specializes in defending himself and his squad with shields.
Mismatch, on the other hand, has thrown together his look from mismatched spare parts. "His minigun has been known to overheat and blow up in his face, but he'll roll with that because his enemies will taste the shrapnel too. When the dust settles, you'll find him scavenging for vital components."
Rock out to the two new trailers, one for each character, embedded below.
[Soure: Jagex press release]