Enter one of the following Cheat keys during game play to activate 
the cheat function. 

Code                          Result
------------------------------------
[Ctrl]+[Home]                - Each weapon for an unlimited.
                               (period for each shelter.)
[Ctrl]+[Page Up]             - The force of gravity by 1 m/s increase.
[Ctrl]+[Page Down]           - The force of gravity by 1 m/s reduce.
[Ctrl]+[Page Up]+[Page Down] - The normal force of gravity.