Epic game, but like everyone else here:
I HATE CREDS. WHY WOULD YOU PUT CONTENT IN ONLY AVAILIBLE FOR PEOPLE WHO PAY?
You should have at least added a way to get those upgrades without the creds. Read what it says in the page heading: "Play Bloons Tower Defense 4, a FREE online game on Kongregate."
WHY DOES EVERYONE SAY IT'S CONFUSING? Haven't you noticed that there's sort of a...briefing screen? No? You know, that little menu that opens up before you start blindly shooting whatever you see?
Lololol funny and fun...If you do make a DuckLife2 like you said, you should add more story...and like the abilty to buy upgrades...and more skills (jumping, climbing, etc.)
Epic game, 5/5...and to all you downraters who hate this game because you can't solve it, IT'S A PUZZLE GAME. DON'T RATE IT DOWN BECAUSE YOU'RE TOO STUPID TO SOLVE IT.
Awesome game...I like how flexible the guns are. I bought the assault rifle and just upgraded it instead of buying different guns, and I used it full auto without stopping, it was epic. I wish there was more enemy variety though. 4/5.