Millie Meter and Her Adventures in the Oak Tree takes young Millie, heroine
of Millie Meter’s Nutrition Adventure, into the forest, where she must save
the oak tree Twit is determined to cut down; if Millie can convince him the
tree still sustains life by bringing him ten photos of living creatures, Twit
will refrain from felling it.

Under the guidance of Eric, a red squirrel, Millie takes her mission and her
camera under the ground, inside the roots, into the bark, up the trunk, among
the leaves, and into the top of the tree. At each stop Millie meets various
tree-dwelling denizens and the player learns the facts about life inside and
around a tree and all the processes that maintain it.

Actions in this game are all accomplished with the mouse, by pointing,
clicking, or dragging. The cursor changes into Millie’s little copter when it
passes over a clickable spot, and there are lots of them; nearly every
object has an explanation or an animation attached to it. In the tray at the
bottom of the main screen are icons for accessing mini-games, keeping track of
photos taken, adjusting volume, language selection, and exiting the game.
During mini-games, you’ll also have icons for help, back, and starting a new
round; the printing icon, available from Millie’s Tricktionary and the drawing
page, takes the form of a rubber stamp.

On the right side of the main screen there is a narrow panel showing the oak
tree, with an inset picture of whatever area you are in/character you are
speaking to at the time. You can move Millie, who always travels in her little
copter, up or down the tree by clicking here as well as by finding the
(sometimes hidden) exits from each room.

The six mini-games become available as you come across them. Two games are
arcade-style and allow for two levels of difficulty – these are “Catch the
Acorn” and ” The Earthworm Labyrinth”. Three games test the player’s knowledge
of a tree’s ecosystem, but are easily answered after playing the main game –
these are “True or False?”, “Who’s That Singing?”, and “Who Lives Where?”. The
last is a picture game that allows you to choose pictures to enlarge or
minimize, turn, and arrange on a printable page. Also available after
completing the game is Millie’s Tricktionary, a book of science experiments
with printable pages.