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