Here is the full list of all 25 The Showdown Effect: Reloaded achievements.
Score 250 kills with the Machinegun in Ranked Showdown
Score 250 kills with the Pistol in Ranked Showdown
Score 250 kills with the Shotgun in Ranked Showdown
Score 250 kills with the SMG in Ranked Showdown
Score 88 kills with the Katana in Ranked Showdown
Score 20 kills in one match with the Machinegun in Ranked Showdown
Score 20 kills in one match with the Pistol in Ranked Showdown
Score 20 kills in one match with the Shotgun in Ranked Showdown
Score 20 kills in one match with the SMG in Ranked Showdown
Score 20 kills in one match with the Sword in Ranked Showdown
Score 25 kills in one match as Dutch McClone in Ranked Showdown
Score 25 kills in one match as Leona Wolf in Ranked Showdown
Score 25 kills in one match as Hank Stream in Ranked Showdown
Score 25 kills in one match as Lance Koboldski in Ranked Showdown
Score 25 kills in one match as Lord Edmund Gauntlet in Ranked Showdown
Score 25 kills in one match as Dr. Johnny Bionic in Ranked Showdown
Score 25 kills in one match as Hailey Skye in Ranked Showdown
Score 25 kills in one match as Thelma Vaine in Ranked Showdown
Score 25 kills in one match as Mr. Shur Foo in Ranked Showdown
Score 25 kills in one match as Mizu Ichiban in Ranked Showdown
Dive onto someone and kill them with the fall damage in Ranked Showdown
Dive through a window in Ranked Showdown
Dive through 100 windows in Ranked Showdown
Throw an item on the ground without hitting anything first in Ranked Showdown
Throw 100 items on the ground without hitting anything first in Ranked Showdown