Like Mrand said, it's pretty frustrating when at the start when you're just dying in the first couple of second with no idea why, but I think the solution is to change the colour or texture of the spikes so they stand out more rather than changing the size. It may also be worth altering the starting configuration so the player has a few seconds of relative safety to get a feel for the controls before they get hit. That aside, you did a great job of making a simple but engaging game loop, I kept going till I managed the win.