Just yesterday I was thinking "There should be a sequel to Achievement Unlocked." Thank you, jmtb02, for reading my mind and creating such an excellent game.
Some people have been complaining that climbing is too slow, here's two tips: 1.) To go UP faster, hold down the up arrow and tap X rapidly and you will go up much faster. 2.) To go DOWN faster, just hold the down arrow, well, down. I hope I helped! :D
The time where enemies flash red and are invincible when damaged should be decreased. Oftentimes I found myself shooting faster than enemies could be damaged.
I think it's a little unfair that a mod can get a game with badges with only 110 thousand plays yet a game like Bloons Tower Defense 4 has about 1.5 million and a higher rating.
 "Flight"){kind=icon}
 "BeGone"){kind=icon}
 "Epic Combo!"){kind=icon}
 "Rocket Toilet"){kind=icon}
 "Reincarnation: The Backfire Of Hell"){kind=icon}
 "Crush The Castle 2"){kind=icon}
 "Reincarnation: Let The Evil Times Roll"){kind=icon}
 "5xMan"){kind=icon}
 "One Step Back"){kind=icon}
 "The Birdinator"){kind=icon}
 "ALL Chuck Norris FACTS 2.0"){kind=icon}
 "Achievement Unlocked 2"){kind=icon}
 "Heir"){kind=icon}
 "Harry Quantum: TV Go Home"){kind=icon}
 "Solipskier"){kind=icon}
 "Remnants of Skystone"){kind=icon}
 "Big Pixel Zombies"){kind=icon}
 "Five Minutes to Kill (Yourself)"){kind=icon}
 "Viricide"){kind=icon}