The cultures of Project Eternity are in a variety of different technological states. Though some remote civilizations are still in the equivalent of Earth's Stone Age or Bronze Age, most large civilizations are in the equivalent of Earth's high or late Middle Ages. The most aggressive and powerful civilizations are in the early stages of what would be our early modern period, technologically, even if they are not culturally undergoing "Renaissance"-style changes.
For most large civilizations, this means that all of the core arms and armor of medieval warfare have reached a high level of development: full suits of articulated plate armor, a variety of military swords, war hammers, polearms, longbows, crossbows, and advanced siege weaponry. Architecturally, these cultures also employ technologies found in Earth's Gothic structures, allowing them to create towering vertical structures.
The most recent technologies seeing use in the world are ocean-going carrack-style ships and black powder firearms (notably absent: the printing press). Cultures with large navies and mercantile traffic are exploring the world, which has led to contact with previously-unknown lands and societies and settlement in new lands. Despite their intense drive, these explorers have been restricted from aggressive long-range exploration by monstrous sea creatures that pose a lethal, seemingly insurmountable threat to even the stoutest, most well-armed ships.
Black powder firearms are of the single-shot wheellock variety. Largely considered complex curiosities, these weapons are not employed extensively by military forces. Their long reload times are considered a liability in battles against foes that are too monstrous to drop with a single volley, foes that fly or move at high speed, and foes that have the power of invisibility. Despite this, some individuals do employ firearms for one specific purpose: close range penetration of the arcane veil, a standard magical defense employed by wizards. The arcane veil is powerful, but it does not react well to the high-velocity projectiles generated by arquebuses and handguns. As a result, more wizards who previously relied on the veil and similar abjurations have turned to traditional armor for additional defense.