Interesting game. I guess the key to surviving as long as possible is to use the walk forward button only if the danger's meter is depleting or is at a low level. And if the monster appears, hold the space bar and run for your dear life.
Edit: I finally beat the game! The forest and the valley areas were fine. I took my time and walked as slowly as possible to make sure that I don't fill up the danger meter. But when I reached the desert part, the danger meter started to fill up when I got to the halfway part of the level. So I had to press and hold onto the Space Bar and ran to the end to beat the game. This was one of the longest game I've played in a Jam.