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