Firstly, yes I know there are many guns that need tweaking and that the devs should do that first but at the same time I like the idea of different guns for the game that seems to rely on 5 of them.
My idea is for a mortar like gun (same projectile drop, same projectile speed, smaller clip size, better arcs, better ROF) that releases small clouds wherever you hit, players within these clouds would take a speed penalty and have their visibility impaired; the speed penalty would be the same regardless of the number of clouds you are in but the visibility would get steadily worse if you were in multiple.
This gun could be used to escape much like tar although you could only effect a smaller area, best for on Galleons or Squids, possibly Pyramidions and Spires as well.
Players could use this as a harassing weapon with a (relatively) flat level of effectiveness, unlike the disparity between how the flamethrower effects noobs vs. vets
For close range ships that rely on ambush (Mobulas, ramming Pyramidions, some death Spires) this gun would allow you to sow confusion on the enemy ship, making it more difficult for you to be spotted by your victim while lowering his reaction speed.
To balance you could make the clouds immobile (makes sense anyway) allowing faster enemies to escape while giving the gun some synergy with disabling weapons (to keep them in the clouds), an arming time could be considered but the idea is for this to be a close range volley attack so you'd have to allow it to shoot a bit farther if you went that route.
The gun could either lack damage or just do a very small amount of impact damage as both it's primary and secondary, many ammos wouldn't be useful but that's nothing new to the guns in this game. Greased (most clouds as quickly as possible) and Burst rounds (for uber clouds) sadly would likely be king like on many guns.
Clouds would be smaller than tar and not be as dense (they don't do damage continually after all) so they should probably dissipate within 10 seconds or so, the reload speed I'm not sure on as it doesn't do damage so I'm tempted to make it very high (comparable to the Gatling), the amount of speed reduction also stumps me as I want it to be noticeable but not debilitating to the point you cannot do anything.
Anyway that's my rambling idea
Here are some rough equivalencies for basic stats
Light Gun Mount
Projectile Speed; Mortar
Projectile Drop; Mortar
Clip Size; 5-10? Adjust for balance
ROF; Banshee
Reload Speed; Gatling
Arming Time; Preferably not?
Turning Speed; Flare
Gun Arcs; Not quite Flare
Speed Penalty; Unknown, somewhere above 25% but below 75%, I want engineer stamina to offset it completely but not by much so I say 75% but at the same time I'd like to not prevent a gunner or pilot from leaving his spot (just make him hate the guy that shot the gun). Alternatively you could make it scale with each cloud requiring players to aim if they really want to limit mobility in one section of a ship, maybe 10% per overlapping cloud? maximum of 70% for 7 clouds.
Visibility Penalty; Unsure, I don't know how to verbalize the amounts but I want it to go from barely there to Tar, the worst requiring you to be in 3-4 clouds at once, should block spotting in increased degrees as well but Muse's spotting mechanic baffles me and most of the people I know so I'll leave that to someone else.
AOE; I have yet to find the sizes of the ships (length, height, width) and it is difficult to extrapolate off of existing guns but I was thinking the AOE would not quite be large enough to fill the engine section of a pyramidion, requiring you to target one area to lock it down if you wanted rather than being able to cover the whole ship.
For added fun and immersion add a coughing sound for people in the cloud, possibly with a greenish hue to the screen?
Anyway do what you will but I like it and thanks for reading.
