The game has been largely reverse engineered and most of the engine is understood. There is a site explaining it (dead link at the time of writing, use the wayback machine). The same author has also released an application called "Lazy shell" that allows easy read and write access to the data.
The third boss, Mack, can be skipped if you jump on top of the goons on the side and talk to the chancellor, as seen here.
Midas river coins
The game only tells you that it has kept the coins in case you return if there is an non dividable number of coins left after giving out frogcoins (if any). So collect an evenly dividable number of coins to skip this text.
Exor two hit KO
This boss is unique in that, due to a coding error, it loses protection against the instant KO Geno whirl attack when the mouth becomes vulnerable, as shown here.