The Destroyer was originally supposed to be a flamethrower (in fact, it still says Fire Gun on the side... oops!) but since I can't tolerate having anything less than perfect, and since it would have taken a Pentium 5-million to run a Gunreal Flamethrower with proper looking fire that could ignite anything it touched (unlike most games with feather-duster flamethrowers that blast walls without even leaving a scratch on them), I decided to make it into The Destroyer instead.

I actually wanted the Destroyer from the beginning, but it was originally part of an idea to allow you to buy special super-weapons using 100 adrenaline (guns such as the Mega-Shotgun and Megagun (as opposed to minigun), both of which would require a Pentium 5-million). I scrapped that idea, and thought it would be a safe bet to make sure there was at least one weapon you could call super, aside form the HRL, which is more of a vehicle-killing machine... and thus, we turned the Fire Gun into The Destroyer, and don't have any plans for a flamethrower.
There are actually several gameplay factors moving against a flamethrower in the first place: I can already see it falling to the bottom of the priority list (much like the Ripper in UT, but even more like the flamethrowers in most other games), *especially* in large maps, where it would simply become useless. I mean, seriously... a flamethrower is anything but a tiny DM map? You wouldn't be able to hit anybody.
But, if in a short time they invent a CPU and GPU that at least doubles the current speed of computers, we'll have to do something with fire.

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Some Gunreal trivia: here are some guns that never made it into Gunreal:
Ice Gun- You could freeze people, then break them. Alt-Fire was an "hasta-la-vista-baby-style" single bullet. I always thought that the most fun kill, though, would be to freeze someone on top of the Torlan tower, then push them off by running into them)
Megagun- A Minigun to insanity - this gun was actually held up by a suit that you wore (just some powered legs attached to the player model), and gave you partial protection on all sides (except the back) just from its bulk (it had pipes and everything wrapping around your sides, going down to your powered legs).
Heavy Plasma Gun (was a sibling to the HRL, for Onslaught)
- There was supposed to be the ability to upgrade your plasma mines by feeding them more plasma, and you could get them as big as a tank (they would start sucking in vehicles that touched them, and you had to prevent them from "hardening" from collecting too much tank metal, and cooling from sitting too long). The Heavy Plasma Gun was designed for 4 things:
1 - "Plasma mine maintenance".
2 - Attacking and disabling vehicles. (vehicles had EMP health, that would drain from electrical damage, until they shorted and stalled)
3 - Killing stuff. (primary fire rapid-fired very bright plasma balls, and alt-fire released a brief-but-devastating beam of plasma death [destroyer-style] that made the gun overheat and have to cool)
4 - Healing things. (the idea was for plasma to be a team-centric element used to maintain vehicles [still is, actually], as well as super-charge the plasma guns of your teammates [try it])
Mega-Shotgun- A shotgun with 5 racks of ammo: each rack was a single shell the size of a pizza, which was slammed from behind by a giant hammer (flack-cannon-style) and fired an entire blizzard of shards for 2 continuous seconds, allowing you to clear whatever was in front of you.
Photonic Rifle- A clean, white plasma-type weapon that semi-rapid-fired invisible shock-rifle-style pulses that gradually charged up players (they would get brighter and brighter) until they exploded, shrunk, or experienced some other adverse effect (1/100 chance that they would become huge and powerful, and 1/100 chance that they would be turned into a chicken, and be able to run around and fling eggs).
Nail Gun- For homicidal maniacs who also enjoy a career in wood-working, and would like to blend the two. It would have been like a weak minigun (around the level of the Acid Weapons... in fact, it would have been very similar to the Acid Machinegun in the way it worked).
Chainsaw - The aforementioned homicidal maniacs would have also needed a cutting utensil...
Lightning Gun - The battlefield electrician's delight - you would have primary-fired a rope with a gripping harpoon at the end, snagged your opponent, then alt-fired to turn him into a large Christmas light. Anyone close to him would have also felt the Christmas spirit.
Vulcan Cannon- This would have been ANOTHER rotating-barrel weapon that worked like a slower rate-of-fire minigun with higher-power shots. The Anti-Armor Minigun fills the role now.
Flamethrower- The idea would have been that it fired REAL napalm (you know, stuff that actually turns everything it touches into a raging inferno) not orange-flavored dust-off. Maybe when the Pentium 6 and GeForce 12-series comes out, we can do something with this... I would love to see Rankin engulfed in very realistic fire.
"Plasmatar"- A plasma rocket launcher. Need I say more? You shoot, stuff dies. (Faster rate-of-fire than the RL, but less damage)