Hehehe, I could never go for more than 5 seconds
Alpha is transparency channel. JPG doesn't support alpha channels so you will have to go with PNG (there are other choices but PNGs are the most popular).
The FPS went all over the place, it would go really fast and suddenly slow down and then speed up again. Try bounding the FPS instead of letting the game loop run wild.
Restarting instead of closing could be simply implemented by having a "start" screen that says click to begin. Try playing around with the code to figure out how to implement that