Races will not be added until the Terran are completed and the map is released to the public. Once you make a building for that race, you cannot contruct another race after. However, towers are not race specific but you can only have one out at a time, except at 30 minutes and on, you are alotted two at a time.

for towers:

There are 3 different types of tower modes, Offense, Defense and Utility, that you can choose which you want for free with the initial tower that is built and they become that, permanently. Attack towers rely on their attack and offense based spells/abilities, they are primarily for attacking at long range and on the opponent's side of the field. Defense towers are for protecting your side of the field, using abilities concentrating on keeping itself alive. Utility Towers have abilities with uses for all kinds of different things. Everything that the towers do, costs energy or minerals. If a tower is destroyed, you may bring it back 5 minutes after it was destroyed with all of it's upgrades returned, but it's energy will be at zero.

Towers will not be race specific.

Each player can build different buildings: Barracks, Academy, Factory and Starport

Barracks: 3 Marines -> 3 Scouts -> 3 Recons (Bonus Light/Bio)
-> 3 Techs -> 3 Grenadiers (Bonus Bio/Armor)
-> 3 Flakkers (Bonus Bio/Air)
(All Marines, different sizes/attacks) -> 3 Heavies (Bonus Mech/Ground)

Academy: Firebat -> Medic -> Doctor (Healing Aura)
-> Surgeon (Healing Buff)
-> Marauder <> AAMaruader
-> Ghost -> Operations (Special Spells/Abilities with building)
-> Spectre
-> 2 Firebat

Factory: Viking -> Tank -> Heavy Tank -> Siege Tank (Bonus to Mech)
-> Fortress
-> Light Tank -> AA Tank
-> Hellion -> 2 Hellions -> Inferno (Bonus Light/Bio)
-> Hellfire (Bonus Heavy/Bio)
-> Vulture
-> Heavy Viking

Starport: Wraith -> Banshee -> Darkstorm (AoE Ground)
-> Dropship -> Medivac
-> Heavy Dropship
-> Viking -> Heavy Viking
-> Battlecruiser (Multiattack)
-> Vessel (Detecter)

We also need to get some kind of special building that uses strictly energy to make units off a cooldown and puts all of the other spawns on it into a short cooldown as well (to prevent spamming). Kind of like a troop center, make it the Bar building and call it the Mercenary Center.

For future reference, the zerg will have less buildings, but are focused on massing units in large bursts or very quickly. They will also be much more heavily upgrade based, since they have less buildings, making it so they can build into whatever is needed, much easier. At the same time, much harder. Thier mercernary building will be "Infested Colony" where they make a shit ton of different types of Infested Civilian-based units. When a zerg building dies, it creates a lot of broodlings as a defense/last stand feature. Broodlings do not provide any minerals per kill. I may also add an ability to each Zerg Structure with a broodling spawn as well, of course broodlings will have a expire timer so they cant be used for offense (too heavily anyway ) broodlings will have a greater rally delay than normal buildings so that they can respond to nearby disturbances more so than assault around itself.

For protoss, they will be more into having different structures. Their buildings can also "teleport" to another position, however once built the buildings must wait 180 seconds before they can teleport and teleporting, is the same as building and to boot, costs 25 minerals. The protoss' mercenary building will instead of create units, cast spells. Quite similar to a offense/defensive tower in this sense, but really a combination of all three. It's price is hefty and is difficult to 'rush.' Spell Nexus can cast Psionic Storm, Recall, Mass Recall, Cloak, Cloaking Field, Hallucination and Vortex, all redone to fit the game and some new things as well. You can buy energy.

So all-in-all, the Zerg will have 4 buildings, the Terran will have 5 (6 if I add a hero building) and Protoss will have 9+.

my current ideas for the towers are as follows:

each tower will ahve one universal upgrade, it's mana regeneration reflects the game's time elapsed. So late game, energy flows fast. this will allow people who didn't build them early on to still have use for them later game and add in a lot more chaos, making them mainstream.

offense towers have long range abilities, like launching missiles and air strikes. things of that nature, but as for a close range defense they don't really have one. maybe some kind of aoe explosion as their only close defense excluding a typical attack. some kind of upgrade for their range would be good as well, so they can constantly support units in the field without expending energy. the basic idea of this tower is for people who went straight spawns early game and build this later game, could use it to push/finish and win games so they dont drag on forever. once 30 minutes hit, this building can get another upgrade to greatly enhance it's energy.

defense towers are all about their default attack and utilizing abilities of that nature. one ability i think is a must have, is to "whistle" to enemy units and make them come to it. They would instead of going to attack whatever, come straight to it and attack it. other abilities like restoring it's health and a repair for nearby structures/itself. a heal beam for units as well, with upgrades to increase it's maximum targets/range/rate. any kind of damage spells it would have, would have to be close range. Making this a viable building for people to build and concentrate on for pure defense of their team, so they could aid/defend with players who went with straight spawns.

utility towers will have a spell that turns 5 minerals into 10 and have a rather long cooldown, like 30 seconds. a spell that gives it's own energy to another building would be ideal to make the idea of energy buildings for each race, more ideal. it can be used to make other towers even better as well. so far that is all that I can think of for it, but im sure it will have many more uses to come, but i would like to focus on it costing minerals and energy hand-in-hand, so people could focus on getting one of these and say a mercenary building, could aid/compete with players who went with straight spawns.

for Zerg:

Spawn: 6 Zergling -> 12 Zerglings -> 18 Zerglings -> 24 Zerglings -> 32 Zerglings
-> 12 Speedlings -> 18 Speedlings -> 24 Speedlings
-> 2 Banelings -> 4 Banelings -> 6 Banelings -> 8 Banelings
-> 1 Bombling
-> 1 Tankling

Evo: 2 Roaches -> 5 Roaches -> 10 Roaches
-> Infestor -> 2 Infestor
-> 2 Hydralisk -> 4 Hydralisk -> 6 Hydralisk -> 8 Hydralisk
-> Queen -> Ultralisk
-> Broodlisk (Spawns Broodlings on attack/death)
->

Spire: 1 Mutalisk -> 3 Mutalisk -> 5 Mutalisk -> 7 Mutalisk -> 9 Mutalisk
-> 1 Devourer -> 2 Devourer -> 3 Devourer
-> 1 Broodlord -> 2 Broodlord -> 3 Broodlord
-> 4 Scourge -> 8 Scourge
-> Corruptor

for Protoss:

Gateway: 1 Zealot -> 2 Zealot -> 4 Zealot -> 6 Zealot -> 8 Zealot

Warpgate: 2 Zealot -> 4 Zealot -> 6 Zealot
-> 2 Stalker -> 3 Stalker
-> 1 High Templar
(Warps to Rally) -> 2 Dark Templar

Cybernetics: 1 Stalker -> 2 Stalker -> 3 Stalker -> 4 Stalker
-> 1 Sentry

Robotics: 1 Immortal -> 1 Colossus

Observatory: 1 Observer (Really long Rally delay)

Archives: 1 High Templar -> 1 Archon

Dark Archives: 1 Dark Templar -> 2 Dark Templar
(Cloaked)

Stargate: 1 Phoenix -> 2 Phoenix (lift makes units air/attackable)
-> Carrier
-> Void Ray

Library: 1 Warp Prism -> Field Prism
-> 2 Warp Prism