Walker


 CHEAT MODE:

 On the title screen (the one where it says press fire to start) simply
 type in 'WALKER' and a red line will then appear in the center of the
 screen. Now whilst playing you can press:

 [Help] and [I] - Invincible.
 [Help] and [L] - Level skip.
 [Help] and [R] - Restart level.
 [Help] and [K] - ?