These hints are more-or-less in chronological order. If you're trying to solve a puzzle without first dealing with the problem addressed BEFORE it in this list, the hint will not work.

I tried to use the bulldozer to get through the door, but it won't back up.

I'm inside; where do I go now?

How do I get up the stairs?

Where on earth do I find the code and name for the computer?

I don't have a weapon, but the Heruka's after me; what do I do?

I got the gun, but there's no ammo.

Okay, I got the loaded gun, opened that room... but the Heruka keeps dodging me! How do I stop her?