Damage feedback

I've noticed a lot of comments about the feedback of damage to the player

Just a small update of adding a red filter to the screen when being hit

May add in some kind of notification on the HUD, once that is cleaned up and not using basic cubes as placeholders

Many more things to do:

 - adding in more levels and variants 

- adding different transforms to level transitions

- more enemy types 

- another playable character 

- alternate fire and interaction with the environment

- story

I'll keep working on movement so it doesn't feel as floaty too