Neat idea, with a lot of potential. I think the feedback is currently feeling very bad tho, a sound effect for the moment to press the button, and indication that the button was actually pressed, a different sound effect indicating that you lost, would all be things that would help the game feel "Not Rigged". Also maybe a "Results Screen" showing how fast you pushed Space, and how fast you should have pushed Space.
Also, spamming Spacebar is pretty viable, you should probably add a way to lose by pressing to early.