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