Characters can build any weaponry that would be reasonable within the scope of Ryslig's time period/setting - ie, something that could also be plausibly obtained from an NPC human. Swords, normal firearms, and even things like flamethrowers would be completely fine, as would bombs appropriate to a roughly 1950s setting. Things like plasma rifles, portal guns, and so on would usually not be, whether or not they're made with era-appropriate tech as a basis. For those characters would need to go through Mana!

Alternatively, if a player has something more high-tech in mind for a specific player plot, this could be accepted on a case-by-case basis!