What is Total Mayhem? 

It's a rebalance that increases player options, and also adds a lot of high-quality Cavedog-style units including a full L3 tier of units.

*** L1 improvements:
- Jeffies and Weasels are quicker.
- Peewees and AKs are quicker too, slightly faster than Flashes and Instigators. The AK now sports the Instigator's laser, making it much more useful.
- Flashes and Instigators are about the only units in the game unchanged... Apart from Instigators having a slightly faster firing rate to more closely match the damage output of the Flash.
- Stumpies and Raiders are slightly slower but have 20% more armour. They have improved range but still fairly light firepower.
- Rockos and Storms have a bit more range and better damage output. Rockos more damage per rocket, Storms fire more rockets.
- Hammers and Thuds have much longer range, they now outrange Rockos and Storms. But they do a bit less damage, have a bit less armour and aim more slowly. They are much more useful now as actual artillery units for taking out point defences.
- AA missile units all have reduced range when firing at ground units - more or less matching the range of point defences, so they'll still be pretty useful for taking out stray Jeffies and Weasels, or for ganging up on small groups of other units - but they will no longer be able to amass fire from a larger number of missile units.
- for added diversity, the Crasher is now an AA laser kbot. It has much shorter range vs ground but does better damage vs ground than AA missile units.
- sea-wise, the PT boats Skeeter and Searcher now have much better skirmish weapons, being much longer ranged (still less damage output than Flashes and Instigators though. Useful if you build enough of them). The Skeeter now has an EMG.
- Transport boats now have teleport loading, are armed with a laser and will unload all units at once instead of one-by-one.
- Metal Extractors can be upgraded for much more armour and a laser weapon.
- LLTs are halved in price and have better range.
- HLTs do more damage, have more armour and have much better range.
- Guardians and Punishers do more damage and have much more armour, and are a little cheaper - although they have a much longer buildtime.
- added L1 defenses (can be built by commander): AA-only lasers (Arm Fury and Core Scythe), short range plasma cannons (Radical and Blocker), and the Sunspot, an Arm EMG tower as a counter to the Core Immolator.
- added L1 units for Arm: the Helldiver, a kind of heavy amphibious Peewee with the longer range lower damage EMG also used by the Skeeter. The Terrier, somewhere beween the Jeffy and Flash in speed and armour. The Janus, a heavy rocket tank.  The Viking, a Rocket Frigate. 
- added L1 units for Core: The Garpike, an amphibious laser tank. The Shodan, a slow-firing HLT tank. The MAK, a heavy version of the AK with AA missiles. The Jar, the Can's smaller brother. The Vanguard, a Rocket frigate.

*** L2 Improvements:
- more armour, more range and/or damage pretty much across the board, albeit in some cases with some cost increases
- Zippers and Freakers are much faster, the Zipper now has a short-burst, high-damage EMG
- Cans and Sumos move much quicker (still very slow) and have much better range
- Shooters and Penetrators have decent armour, much better range and aiming
- Spy kbots have much better line of sight range, and have become saboteurs as well - you can tell them to attack other units and they will set off a detonator next to them. It has high damage but a long reload time though, and be warned using this will decloak them and expose them to enemy fire.
- naval-wise, advanced construction subs have much smaller footprints. Missile ships get better range, higher damage, better AA missiles and better armour. Subkillers get better armour to suit their cost. Cruisers get a better depth charge. Battleships have more armour and massive salvo fire (this evens the score between the Millenium and Warlord a little).
- Annihilators get 50% more range and much more damage per shot, Doomsday Machines get better BLOD aiming and doubled range on the blue and green lasers. Both get much better damage per shot.
- Ambushers and Toasters get much cheaper, and much more damage with bigger splash damage. They get improved range but are still outranged by Guardians and Punishers.
- Added defenses: Archgun and Chainsaw, rapid cannons with battleship range (20% further than Guardians/Punishers), and the Arm Artic, a pop-up gauss cannon counter to the Core Viper - which incidentally has a much higher power but slower firing laser - more than double the damage but about half the fire rate of the HLT.
- added L2 Arm units: the Rover, a rotating gattling-style artillery cannon version of the Fido. The Shocker, a crawling all-terrain heavy artillery. The Cipher, a stealth gauss tank. The Messenger, an annihilator ship, and the Pike, a heavy battlesub.
- added L2 Core units: the Reaver, a 4-legged heavy riot kbot with aa missiles. The Gargoyle, a mobile Doomsday Machine. The Mammoth, a heavy artillery tank that is also armed with riot cannons. The Omni, a rocket ship that fires heavy tracking rockets as well as AA missiles.
- Also added for sea: Arm Thorndado bomber that drops depth charge bombs, the Sontor torpedo gunship, underwater moho mines and moho metal makers.

*** Level 3:
- Arm gets a counterpart to the Core Gantry, the Shelter. Factories are also added for vehicles, ships, aircraft and hovercraft (although as of 6.8 L3 aircraft and hovercraft have been removed pending a revamp). 
- L3 construction units are added that can build Uber Fusions (massively palatial units producing over 10k energy and trading some of that energy for over 100 metal output), extra-long range radar towers, L3 AA, nuke cannons. The Buzzsaw and Vulcan are also moved to L3.

*** Other notable changes
- metal extractors cost 50% more metal, are about 30% tougher and produce 20% more metal. This makes early economy startups shorter and games faster paced, and makes expanding to seek metal patches much more important. Mohos are unchanged in cost but produce 60% more metal (!!) for an increased energy cost.
- Solars are much cheaper and will be more worthwhile as an alternative to the less reliable but still potentially much better value wind generators.
- Pop-up advanced solar collectors are available for both sides built by L1 construction units (but not the commander). They produce triple the energy of regular solar collectors, the same amount of energy used by a metal maker. 
- Construction Kbots move much more quickly - still slower than Construction vehicles, but faster than the Commander, and they are cheaper than the vehicle counterparts, offering better value nanolathing rate for the cost.
- factories have mostly had their nanolathe rates doubled, making games more faster paced but also meaning assisting a lab with a construction unit yields less reward.
- Single airpads are shifted to L1 construction units. Quad air repair stations are now available for L2.
- Targeting facilities are halved in cost.
- Nukes cost 7 times the metal! But can be built in less time. Antinukes cost roughly double the metal.
- Cloakable fusions are just under double the cost and produce double the energy of their non-cloakable versions. They also cloak for much less. Underwater fusions have also been boosted.

***** New in this version 6.8: *****

- Underwater metal extractors get torpedo upgrades just like the land ones do.
- New Extra-long range T3 radar towers.
- The Arm Direwolf giant walking Annihilator fido, and the Moose artillery hovercraft.
- The Core Mammoth Artillery tank, Viceroy Artillery hovertank and the Core Replenisher, an air repair Tortoise (as a counterpart to the Arm MARS Mobile Air Repair Spider).
- A few bugs fixed, including a bunch of minor script SNAFUs and the Ambusher super-short buildtime (thanks Psycros for spotting that).
- Aircraft are now much safer from non-air units - they have been doubled in armour and AA weapons now do double damage vs aircraft - meaning non-AA weapons are halved in effectiveness. 
- Also all non-air weapon turret aim scripts have had their vertical aiming speed reduced by half or more, meaning responsiveness in aiming up at aircraft is much slower. 
- On the flip side... Line bombing has been reduced in effectiveness. After their initial payload of 6-10 bombs, bombs will be dropped at increased intervals of up to half a second. That means you can still linebomb, but it wont be the same endless line of destruction.
- T2 radar and sonar aircraft have had a big upgrade: extra armour, visibility, speed and manueverability. Massive visibility. Still much slower than Peepers and Finks, but they should actually be useful as spy planes now.
- Rapiers now fire rockets in bursts of 3, with a higher damage output. Better vs larger targets, but tend to miss smaller targets a bit - such as the Commander.
- The L2 units which have AA missiles as secondary weapon have had their AA weapon nerfed a bit.
The Capital Ships have been nerfed a bit - 20% less armour and 10% more cost. They are still waaaaay scary, don't you worry. The concern I had was they are more or less vulcan/buzzsaw ships (albeit with a bit over half the range and less than half the damage output) with super-armour and super-close range weapons. This doesn't change that... but they should be a bit easier to kill and take a smidgin longer to build now. Their big vulnerability remains: subs.

In addition, there have been quite a few changes since the last released version of Total Mayhem. 

Consistent metal output of all constructors and factories. Now you will know exactly how much metal you're using and there will be no surprises. A lot of energy costs have been adjusted too, not to a constant level but there shouldn't be too much extreme energy drain.
A lot of units are gone. Some them I will miss... but the ones that were removed were either redundant with other units, or were removed to increase side diversity. Some of them may yet be added back in again in improved form. 

On the plus side, the Spider Pack 2012 and the Tortoise Pack are now included! This adds a new plant for each side, adding a bunch of all-terrain units for Arm and a bunch of slow armoured amphibious units for Core.