User blog comment:J. Severe/"Phineas and Ferb: Quest for Cool Stuff" officially announced; coming to 360/WiiU/Wii/3DS/DS August 13th/@comment-142.105.244.214-20130501013246/@comment-3477287-20130516234129

I haven't read all the reviews, but I'm pretty sure they were aware. Reviewers are pro gamers (usually) who've reviewed hundreds of games so it's highly unlikely that they'd miss something like that. They're the type of players who finish actually hard games like Dark Souls and Ninja Gaiden. It's possible AT2D's hard mode was pretty easy compared to their standards.

I also played hard mode and to be honest, regular difficulty felt like "ultimate wuss mode" while hard mode felt like "very easy".