A solid puzzle/platformer. You can't ignore the instincts to compare it to Portal, however it's only somewhat similar because of being force to become a test subject and the 'evil' faceless guiding force.
I found this fun and challenging, not to mention trying to gain the grapefruits AND finish the level the way you think it should be completed. I can't find glaring faults with your game, perhaps it could be improved graphically but I quite like the retro appeal. Your controls are straight forward and the game, generally speaking, isn't complicated to the point that get bored or frustrated.
Great job.