Introducing 0.5!!

In this update, I added in a main and pause menu!  Not only can you put the game on hold to take break if you need to, but you can also choose between Infinity and Mortality mode!  You can deduce what those names mean on your own--it's pretty straightforward.

In the next update, I want to add in a test stage with test enemies, experiment with delay clouds, and play with different shot sprites!