i found a "shortcut" to the untergroundbase:
u have to go under the freeway and than as far as possible to the left, the program have over there a bug, so that the char. sink into the ground, first turn right, cause the char. move opposite direction and than left to move to the base. don´t worry to get to deep u can get back to the groung when u start to jump, than he moves a bit up
First key on the top of the cupboard, at the left of the first room; second in the bin/cup, on the chest of drawers at the right at the first room; third key in the robe in the second room.
The there are also a puzzl part at the sofa, in the right sleeve of the shirt and at the upper bookstack in the last room, a peace of paper in the lower stack and glue in the vase at the table in the last room
 "Frontier"){kind=icon}
 "Red Planet"){kind=icon}
 "Mass Mayhem 4"){kind=icon}
 "Friends Room Escape"){kind=icon}
 "Rebuild 2"){kind=icon}