Finalising the game

Added some feedback received on the game and fixed important bugs:

• Added a sound that plays when you hit an enemy and when you are hit
• Increased size of player attack hitboxes
• Gave timer placeholder digits
• Rebalanced the second level (it's a bit fairer now but overall a bit more difficult). Also added text in the Laser turret intro room.
• Rearranged and changed the tutorial text.
• Fixed enemies spawning outside of the last room of the second level, making the game unbeatable (what happens when you don't playtest)

I probably won't add a leaderboard cuz the jam is over and there really isn't any point, I'm also really lazy.