Has anybody ever been able to outrun the troll in the cave or outswim the shark? When I see either of those 2 monsters I am dead unless I am at the edge of the screen and the next screen is a safe screen

You can't out run either one of them. With the troll you have to wait a little while to see if he comes and if he does, quickly exit the screen, then go back. As you probably know, he comes a lot, so it can be frustrating having to keep going back and forth. With the shark, you just have to keep trying. It tends to come more often if you're going in a wrong direction. But it'll still sometimes come even if you are

Does this work if you're not on the first screen of the cave (the entrance screen)? If you're on the 2nd screen when he appears, can you get back to the entrance in time? And I occasionally encounter him on the 3rd screen (the screen directly west of the chasm screen) and then I can't even move before he gets me.