1. Pistols. Unlimited ammo and the first gun available to the player though extremely weak at first, it's ridiculously cheap upgrades can make these dual pistols have more firepower than a normalolvers.
2. Shotgun. A Multi-shooter with a slow firing rate and a wide kill radius that is ideal for killing clusters of green aliens though with a couple of upgrades it can serve well till mid-game.
3. Grenade Launcher. A weapon with a small explosion. It has little more damage than shotgun and little faster firing rate. Can be inaccurate at times so backpedal if it's not hitting anything yet.
4. Minigun. A rapid fire gun with low damage and average accuracy. With high accuracy this is a strong weapon. In theseus ROTH, it's a machine gun.
5. Rocket launcher. A very slow shooter, with a big explosion, and high damage. This weapon is good for taking a large crowd of armored multi-arm aliens.
6. Freeze rifle. A gun with same rate as pistols, sorta-high damage, good accuracy, and is useful. This gun may not overpower minigun or rocket launcher but it is the best for weak enemies.
7. Plasma rifle. The slowest fire rate, Highest damage, and rocket launcher explosion sized explosion. In some cases, this is the best weapon (even better than magma cannon) like when you're taking a crowd of green armored rhinos.
8. Flamethrower. The strongest weapon, but is melee. Is preferable for melee combat.
9. Magma Cannon. The 2nd strongest weapon (2nd to flamethrower) but is the best because of range. Is the essential weapon for level 10.