Space Elite Force 2 in 1 (UP)

I am not sure if it is a glitch, or if the game is just poorly designed, but there is a trick that will allow you to upgrade all weapons and equipment very quickly and easily for S.E.F. 1.

While the game isn't really difficult, this method will allow you to unlock everything without having to replay the campaign multiple times.

1.) Start a game (I did this on normal, not sure if it works on Hard).
2.) Play through the first 2 stages. DO NOT spend any credits during this time. (The default secondary weapon is efficient to destroy larger enemies and bosses).
3.) When you reach the start of Level 3, you should have over 1000 credits. While the number doesn't really matter, having 1000 or more is preferred, as 1000 is the cost of the most expensive upgrades.
4.) At the start of level 3, intentionally get yourself killed.
5.) At the game over menu, select 'Garage'.
6.) Spend as many credits as you can on upgrades.
7.) When done purchasing upgrades, select 'Restart'.
8.) You will restart level 3 with all purchased upgrades. BUT, you will see that you will also have all the credits you had previously.
9.) Get yourself killed again, spend all credits again. Rinse and repeat until you upgrade everything.