Only achievements I don't have at this point are nose diver (I wonder if its working as I have killed myself in each wave) and vegan (tried it with Bob just now with the horde fighter but accidentally ran over a heart at some point >_<.
Up until actually having to learn the counter intuitive controls to get my kongai card, I just wrote this off as crappy game. Now I see its pretty fun, and has music reminiscent of a Mega Man game to boot.
How to do the zamboni bonus: Try to kill Psychogoldfish near the very top left corner so that when the round ends you can be standing at the very top left corner. As soon as you have control of the zamboni head all the way down, and then start heading right until the percentage changes. once that percentage changes you know you are in a new row. Head to the top till you complete that row. Then head right again until the percentage changes again, and so on.
Also, I have no idea why people complain about wadalf. He is pretty easy compared to the boss before. Just run from the zombies and don't stand directly in front of him. (Like in all old school beat em ups, it is your best stragegy to start attacking from below or above while moving toward them).