I think I found some Easter eggs where you fall in the ground under a box, there is a sign on a building that I can't seem to get to, pressing alt allows you to jump, and if you crouch when you meet an enemy, a bunch of scrambles appear.
Also, when you jump on one of the trampolines, there is a face of somebody who looks like Slappy from Goosebumps.
Also, when you eat a fruit, you can return to the spot the fruit once was and the capybara says a heart. Also, you don't need to press down and to the side to exit a ladder. Just the left or right is enough. Also, you can eat the fruit even if you're dead, or even die again. There is also a sign in a pit in the first construction level that says "No Easter eggs here, sorry."