Bomb - Not implemented yet
Beam - Beam weapons are generally slow firing high damage weapons. They come in Cutting Beam and Thermal Beam varieties. When they fire they form a solid line between the unit firing and the target. They have a huge credit cost but they don't take up much space. Currently a great deal of Specials research must be done before they are worth using.
Pulse - These are, in a sense, energy projectiles. Plasma weapons would fall into this category as an example. Pulse weapons tend to take up less space than other weapon types, but their damage is severely limited initially. Later, with sufficient Specials research, they are excellent weapons.
Mine - Not implemented yet
Missile - Missiles travel at a set speed until they run out of fuel. They can track targets and home in on them. To balance the fact that they do take time to reach their target, missiles are allowed to continue traveling for as long as they have fuel. In other words they do not have a set maximum range. Missiles must have either an explosive or a chemical payload. Currently disabled due to the performance hit they caused on the servers. Hopefully a solution will be found and they will be added back in by release.
Projectile - The Projectile weapons category includes both projectiles with a secondary payload as well as those without. A secondary payload will affect the type of damage caused by the weapon. Projectile weapons in the game tend to be large and have good damage.