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