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