"aLPHa" by DpEpsilon

I wrote this code a while ago, I'm currently in the process of cleaning up.
Forgive me if it's too messy.

Video URL: "http://www.youtube.com/watch?v=AQ-oFrQP_Cg"

 Instructions:
 To start the game:
 1. Wait for the load
 2. Press a button when prompted
 3. Press the left button
 The game will start
 
 How to play:
 Tilt the board left and right to move the ship on the botton row
 The ship will stop at either edge.
 
 Press the left button to shoot the lazer
 If you shoot an enemy, you gain a point
 You have to wait 500ms to charge the lazer between shots.
 The D13 LED will be on when the lazer is charged.
 A sound will play when the lazer is shot and
 another sound will be played immediately after
 to signal a charged lazer.
 There is a sound for missing an enemy saucer and
 a sound for hitting one.
 
 If an enemy shoots at the Earth below, you will lose a life.
 The LED Shift Register is a count of how many lives there are left.
 You have 8 lives to start with, this is your maximum.
 You will gain 2 lives every 50 points.
 
 Enemy saucers become 200ms faster to shoot every 50 points.
 The fastest speed for a saucer to shoot is 3000ms.
 The original speed for a saucer to shoot is 6000ms.
 The enemy saucers are fastest after 750 points.
 Over time, enemy saucers are faster to appear.
 
 The maximum score is 65535 points (max val of unsigned 16-bit int)
 Striving to acheive the maximum score is unrealistic and should not be attempted.
 
 
 In the options menu, there is normally two options:
 HiScore and Playback
 the playback option will not appear if there is no valid film saved.
 A film is invalid if the last game was not completed.
 There can only be one saved film.
 
 Highscores are saved as 3 letters and the score.
 You may reset this to N/A 0.
 
 Saved Films may not be complete if a game is extremely long.
 These films will terminate as soon as the film player
 has reached the end of the EEPROM if health is not depleted before this.
 
 If the potentiometer value is 0 at startup, the game will be muted.
 You can change this in the main menu by
 taking the pot off zero and then back on zero.
 This is a toggle can be used to mute it again.
 If the game is muted, a mute symbol will appear on the main menu.
 
 To pause a game or a saved film, press the right button
 There will be an option to exit and an option to resume.
 When pausing a game, the current score and the highscore
 are shown. When pausing a saved film, only the current score
 is shown.
 
 When the game has ended, you will see the text "GAME OVER" and
 your score. If you have acheived a high score, you will see
 the text "New HiScore!" flash. To advance from the game over
 screen press both buttons.
 
 If you have acheive a highscore, after the game over menu,
 you will be able to type in three letters to identify yourself.
 Use the pot to choose a letter and the left button to advance.
 Fully clockwise is a blank character.
 Press the right button to backspace.