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