Here is the full list of all 21 Woah Dave! achievements.
Defeat the mothership in Peoria!
Your name is POO!
Kill a rare alien!
Ride a UFO!
Get killed by a UFO beam!
Collect three hundred pennies!
Collect two hundred pennies!
Let a Woah Block get blasted by a UFO!
Destroy a Woah Block with another Woah Block!
Let two platforms get blasted by UFOs!
Kill a UFO!
Collect one hundred pennies!
Kill 10 or more enemies with 1 Woah Block!
Throw a Woah Block in the Lava!
Hit an Eyebat!
Earn your first penny!
Collect four hundred pennies!
Collect five hundred pennies!
Collect one thousand pennies!
Defeat the mothership in Fort Bragg!
Defeat the mothership in West Haven!