You are dropped into this pool. Swim to the surface and avoid being grabbed by the tentacle monster.
Walk to the right and the next frame loads. Otherwise, a tentacle pulls you to a watery death.
This elegant pictogram explains the simple controls. The circle is the control key. For example, to run, hold control while pressing the right arrow.
Control + down-arrow + right-arrow gives you some extra reach to squish the leeches in this next pane. Continue right to another pane with more of the same. Note the hanging leech about to drop from above -- be especially careful to avoid these.
Advance right one more frame and be met by this big cat, previously lurking in the background.
Time to backtrack left - quickly.
Run left through all of the frames and leap to this vine.
You'll swing right, Tarzan style. Time to run to the right.
Run right through all of the previously-visited frames. The cat is zapped by an approaching alien.