This is a hard one. Kill 100 enemies in 1 minute. Try using autoaim and fast bullets.
Persistent bot exterminator
Like 100 kills in 1 minute, except you have to keep the rate for 5 minutes.
I thought it’s impossible. You proved me wrong.
Kill 30 enemies that are in process of eating an ally (ghost) in 1 minute.
Eat too many (more than 10) snowflakes within game life. Snowflakes will be present in Christmas level when its Christmas.