When you destroy an enemy or a meteorite, gems may come out randomly. Weaker is your ship and higher is the probability to collect some gems. The winning strategy consists in gathering as many gems as possible with the first vessels that you pilot.
There are 5 kinds of gems; each has a different power.
A green gem
promotes you up of one level in the range of the available options.
A red gem
is worth two greens
A purple gem
restores the level of energy of the Spaceship. If the level is already at its maximum, a powerful circular shock wave is propagated by the Spaceship that destroys everything it strikes.
The yellow gems
provide your Spaceship with orbital satellite protections that protect you from being hit by enemy’s fire. These protections can be damaged too. If you can gather 6 satellites, they will attack the opponent with powerful electrical shocks each time you fire.
Notice that the yellow gems
restore the energy of your satellites.
The blue gems
increase your score. You can have them multiplied by 2 or 4.