Prototype v2 - Critical State, Game Over

Hi everyone!

This time I added a critical state that is taking effect when the player has one heart only.

In critical state, the game plays a version of the main music in the minor interval and lower, and a looping sound effect is also playing.

There is also a visual effect on the player character: its color changes in fixed intervals.

Now you know when you are in trouble!!! Go loot some hearts!

A game over animation has been added on top of a death animation for the player character. 

Now you know when you lost!

Small things have been changed or added: an arrow to indicate where the player should go in the main screen and the controls guide is now bigger.