Steam is a color matching game with a strong arcade element.
The player controls Tisha, a little girl riding a steampunk locomotive
shooting colored balls from a mounted cannon at ball dispensers (in the first
levels they are mole mounds). The train tracks circulate those dispensers as
they keep filling the inner field around them with balls. Matching 3 or more
balls of the same color makes them disappear. If the spheres accumulate, a
floating time bomb appears. Its detonation ends the game.
Special balls with symbols are thrown randomly on the field. They act as a
power-up when matched. Nuke balls explode surrounding balls. Haste balls
temporally increase the train speed. Color bomb balls pop all spheres of the
same color on the field. Time balls temporally stop the dispensers.
A hollow pole with a factory whistle at the left-side of the screen slowly
fills with each match. Matching spheres also gives extra ammunition for the
weapons. The level ends when the bar is complete and the whistle blown.
The train movement is controlled by the keyboard and the cannon aiming and
shooting by the mouse. Some levels have gates, balls or enemies on the tracks,
stopping the train movement. Other levels have pinball slider tracks and
Enemies throw bombs that stop the train or the cannon from working. Most can
be killed with one of the weapons, although some have to be color matched with
a ball to be destroyed.
The weapons can be selected with the mouse wheel or pressing a number key.
Besides the default ball-shooting cannon, there is a weapon with homing bees
that wait for an enemy came out from hiding to attack it. The gun shoots a
bullet that pops balls and kills vulnerable enemies. The laser cannon shoots a
beam that destroys everything in its path. Tisha also can throw herself on
balls and enemies, eliminating both in a kamikaze attack.