Machinegun
Lvl3 machinegun is a highly improved AA.
Lvl4 machinegun works as a suppression weapon.
Lvl5 upgrade shoot 1 heavy bullet that explodes into frags. Really efficient against heavy missiles.
Blue upgrade is a high accuracy minigun. Fire more than 100 projectiles in 5 sec.
Red upgrade is like the blue upgrade, but with fragmentation bullets.

Sniper
+1 pierced armor piece during upgrades.
Blue upgrade is a high accuracy sniper which fire an Amour Piercing Incendiary projectile.
Red upgrade is like the blue upgrade, but pierce a lot more and one shot devices or weapons.

Mortar:
More splash damage during upgrades.
Blue upgrade is a semi-automatic mortar which fire 7 projectiles each burst.
Red upgrade fire 30 projectiles at once.

Buzzsaw (Moonshot)
More projectiles fired during upgrades.
Blue upgrade fire anti-metal saws.
Red upgrade fire 2 wave of 15 anti-metal saws.

Missile Silo
Lvl 3 upgrade fire a super fast nuke.
Lvl 4 upgrade fire a nuke which divide into a large wave of swarms.
Lvl 5 upgrade fire a nuke which have an EMP range.
Blue upgrade fire a nuke which have a high negative impact.
Red upgrade fire a high explosive nuke which have a lot of EMP range and impact.

Shield Dome (High Seas)
More protection capacity during upgrades.
Lvl4 upgrade generates the dome randomly.
Lvl5 upgrade generates a dome directly.
Blue upgrade generates a shield sphere that protect against shootable projectiles.
Red upgrade generates a shield sphere that stops every projectiles except Firebeams.

Marine Missile (High Seas)
Same upgrades as normal missile silo.

Harpoon mkII (High Seas)
Projectile detonation can be controled.

Flak
Lvl 3 upgrade is an improved shotgun which does armour piercing damage.
Lvl 4 upgrade fire frags projectiles.
Lvl 5 upgrade is like lvl 4 shotgun, but detonates 2 times.
Blue upgrade is a powerful shotgun which fire a lot of projectiles.
Red upgrade fire 60 explosives projectiles in one burst.

Smoke Launcher (Moonshot)
More projectiles fired during upgrades.
Level 4 upgrade fire bombs which have an EMP effect.
Level 5 upgrade fire bombs which have acid effect.
Blue upgrade launch a projectile which flash the entire enemy base. Block builds during the flash effect and disrupt missiles at the impact.
Red upgrade fires 25 explosives projectiles.

Rocket Launcher
More projectile damage, anti-air resistance and fired projectiles during upgrades.
Level 5 launch 3 high explosive EMP Rockets.
Blue upgrade launch 5 high explosive rockets.
Red upgrade fire a high speed rocket which had a lot of knockback and splash damage.

20mm Cannon
More projectile damage, impact, fired projectiles, fire speed during upgrades.
Blue upgrade launch an HE (High Explosive) shell which does a lot of splash damage and impact.

Cannon:
More projectile damage, splash damage and radius, impact, during upgrades.
Blue upgrade launch an APHE (Armour Piercing High Explosive) shell which does a lot of piercing damage, splash damage and impact. Shields stop his projectile piercing capacity

Howitzer (Moonshot)
More projectile damage, splash damage and radius during upgrades.
Lvl 4 howitzer fire a high impact projectile.
Lvl 5 howitzer fire an incendiary projectile.
Blue upgrade projectile explodes into multiples little howitzers shrapnels. Divided projectile does not collide themselves.

Deckgun (High Seas)
lvl4 fire 4 high explosive projectiles
lvl5 fire 5 high explosive incendiary projectiles
blue updrade fire a big High Explosive Squash Head (HESH) which do concentrated impact and high explosion damage.

Firebeam
Flammed projectiles does not expire for upgrades. (Level 1 firebeam still had his flaming conversion)
Lvl 3 has a long fire period to let the time to convert projectiles into indeff flaming version.
Lvl 4 has a really fast fire period and do a lot more damage.
Blue upgrade fire longer than lvl4 with similar damage.
Level 5 add splash damage to projectiles. Projectiles which already do splash damage are boosted too.

Magnabeam (Moonshot)
More attraction radius and force during upgrades.
lvl 3 upgrade: the beam can penetrate materials.
lvl 4 upgrade: the beam does some damage.
lvl 5 upgrade: the beam is incendiary.
Blue upgrade fire a magnetic field at low speed. You can concentrate projectiles in it for more damage

Laser
More damage during upgrades.
Blue upgrade fire a projectile which does a really high impact. Can be defended by shields.