Change Level Settings
 Under the beachhead directory you'll see a list of all the
 levels in the game: 
 
 Level_00
 Level_01
 Level_02
 etc
 to
 Level_60 
 
 If you open those in notepad you can modify any of the levels
 settings. Incuding type of ammo and the enemys agression... 
 
 //Bullets, Projectiles, Missiles
 Ammo 250 15 15
 Time 120
 //Tank, Jet, HelicopterGun, HelicopterRocket (range:1-9)
 Aggression 6 6 6 6 
 
 Just change the numbers beside "Ammo" to whatever you want, or lower
 the agression of the enemies to give yourself a little breathing
 space.  
 
 
 Additional ammunition:
 Note: This procedure involves editing a game file; create 
 a backup copy of the file before proceeding. Use a text 
 editor to edit one of the "level_*" files in the game 
 folder. Locate the "//Bullets, Projectiles, Missiles" 
 section and increase the three numbers that follow the 
 "Ammo" entry that is underneath to set the amount of 
 bullets, projectiles, and missiles (in that order) that 
 will be available in that level.
 
 Change enemy aggression: 
 Note: This procedure involves editing a game file; 
 create a backup copy of the file before proceeding. 
 Use a text editor to edit one of the "level_*" files 
 in the game folder. Locate the "//Tank, Jet, HelicopterGun, 
 HelicopterRocket" section and decrease the four numbers 
 following the "Aggression" entry to lower how difficult 
 the enemy tanks, jets, helicopter guns, and helicopter 
 rockets (in that order) will be in that level. 
 Note: The numbers must be from 1 through 9.