I want my campaign world to have more of a Dying Earth/Barsoomian feel, so I'm trying to reskin and expand options to achieve that. I like the idea of having beam guns and airships, at least in the largest cities. The following are a few items I intend to add to the equipment list, which I'd like some commentary on. I intend to update this thread with more rules additions and ideas as I come up with a semi-usable form of them. Mostly I'd like people to check them for balance.
1. Spike Throwers come in hand-held and long-arm varieties (pistols and rifles, essentially.) They're temperamental, but effective, electromagnetic acceleration weapons with internal power supplies and magazines. A magazine holds ten projectiles, and the internal power supply is good for ten shots. The current amount of power and projectiles is shown with a row of LEDs along the side of the casing, which light up when the user's finger is on the trigger. They are considered piercing weapons and may not be used by clerics, nor may they be used by blade-dancers because they are ranged.
A spike thrower is not limited in the number of Cleave attacks the user may make per round, although the number may be limited by the users level.
Exposure to water, mud, falls, or any other situation the DM deems appropriate will damage or disalign the spike thrower, and it will be unusable until repaired in town by a PC or NPC with the magical engineering proficiency.
The hand-held models have range as a thrown spear (20/40/60) and cost 1,000gp. They deal 1d6 damage, and are +1 to hit. They are not considered magical. They may be used by Mages.
The long-arm models have range as an arbalest, deal 1d8 damage, are +1 to hit, and cost 1,500gp. They are not considered magical. Mages are considered nonproficient in these as they are martial weapons.
A magazine costs 20GP for the hand-held models and 30GP for the long-arm models. They must be recharged at a Power Station when the internal battery is dead.
2. To determine whether a community has a power station, look at the 11-100 bar on the market class table. A class IV market will always have a power station; if a power station is available it may recharge anything all day long. Class V markets have a 25% chance of having a power station in town, Class VI markets have a 10% chance. The fee for recharging batteries depends on the item being recharged. It is 15GP for a spike thrower (which are power intensive and usually subject to surcharges and fees), and usually much less for lights, household batteries, or similar.
Power Stations are large armored bricks of weird science technology. They are difficult to move and phenomenally expensive, but last indefinitely. The formula to make them dates back to the era of the first colonists, and is thoroughly polished at this point. To be moved from one place to another they must be dismantled and moved via multiple ox-carts. They cost 25,000 GP. In a community with a power station, the non-destitute citizens will have access to electric lights and other minor conveniences.
3. Blue Glow Lanterns: these are artificially powered lanterns. They cost 500 GP, and have an effective illumination radius of 40 feet with a weird blue-tinted light. The internal battery lasts for 24 hours (They can be turned on and off, but track each any turn during which they are illuminated as using one turn worth of charge, if your PCs try to get that detailed and stingy.) They're resistant to breakage and are waterproof to a hundred meters or more. The cost to recharge at a power station is 5GP.
4. Baleful Rods: While they're called Rods, these are nonmagical weapons that emit glowing red heat-beams. Because they are weapons, the fighter may apply their bonuses to attack and damage rolls with them. They may be used by mages and clerics.
A Baleful Rod costs 5,000 GP, and has a unique self-regenerating power supply. They may not be recharged at power stations. They have five shots available per day, with an indicator just as the Spike Throwers have (although they have a small firing stud rather than using a firearm-style grip-and-trigger arrangement.) They have range as a thrown spear, and do 1d6+2 damage. Each night at local midnight (clever players might use this to keep track of time while deep underground) they switch from one internal power supply to another, and have five shots available again. The other power supply recharges over the course of the next 24 hours. The power supplies cannot be switched manually, the only control on the exterior of the rod is the firing stud.
A baleful rod is not limited in the number of cleave attacks the user may make per round, although the number may be limited by the user's level. Additional cleave attacks DO NOT use additional charges, as the skilled user may "sweep" the beam across multiple defenders.