April Fools’ Day content hidden in Resistance 3?

Is Insomniac Games toying with us or do they have something planned for Resistance 3 on April 1st?

The developer teased via Twitter, "We may have hid something in Resistance 3 that will show up on April Fool's Day if you play the campaign."

They did, however, give some hint.  "Try the boat level.  Maybe."

Oh, boy.  Better start gearing up for all of the April Fool's pranks that are sure to arise on April 1st.  Here's a tip this year, don't believe everything you read on the internet on that day.

But for some reason, I'm tempted to believe this from them.  After all, they did say they were "totes" serious.

What do you think the April Fool's Day hidden Resistance 3 content will be?