I don't know the game that well. Basically, every time I tried to enter that room, it kept forcing me back out. Maybe it was a bug? So I had no idea if you were suppose to enter at that time or not. Like I barely did any of the other puzzles. As I was entering the room, I was pounding the action buttons but I don't know if its cause a rat is hitting me as I go in that I'll stay inside the room.

I promptly die to the boss inside cause I have no idea what to do in there nor do I have any items to really fight it.

Was playing through the game for my first time on just the PC-DOS version,

I found a glitch that may or may not be helpful cause it looks like it lets you skip areas entirely and I just found it by accident.

In order to successfully complete this run, what is counted as all enemies? Do you need to defeat the helicopter too or is it simply defeating all the crooks and killing Hans at the end the normal way by shooting him out the window?