Some game modes that can be added (a lot) later in the game:
KING OF THE MINE
No player can make mines and there is one mine equally distant from all players on the map. The mine will have 3x production speed to make up for only being 1 mine. Martys will not be able to destroy this mine, only the drillers/specs occupying it. To win, a player must gain 150kg of Neptunium (can be changed), or be the last man standing.
TEAM DEATHMATCH
Host can decide how many teams there will be - randomly assigned, or set before game. Energy and Neptunium is shared between players, and drillers cannot harm an ally's base (they would work like gifts). The Neptunium mine winning limit would be raised accordingly. Team to reach the limit first wins, or last team standing.
CAPTURE THE DRILL
A "Drill" or flag starts out on an outpost equidistant from all players. Those who capture it (it takes up a specialist slot) and bring it to their Queen gain a point per every six hours held. First to 16 points or 4 days (can be adjusted by host), or last person, wins. Could also work with teams.
IRONCLAD
One random player starts with Ironclad status meaning they get 3x (scales with amount of players) boost to shield, energy and driller production. All other players try to destroy the Ironclad's Queen. The person to capture the Ironclad's Queen becomes the new Ironclad, gaining the boost status. The just defeated Ironclad loses his boost and his Queen is reset in a random outpost of his (if none left, he is eliminated). First person to be Ironclad for 3 days, or is the last man standing wins, except the first person who needs 4.5 days to win (the first 1.5 days don't count, so people can get their bases started).
CRAZY SPECIALISTS
Only one change: all specialists have their effect multiplied by 2. (Helmsman travels 4x speed, Tycoon increases driller production by 100%, Martyr range increases to 50%, etc)
SEA MONSTER
An AI (very basic, I'll explain in a second) starts equidistant from all players. The AI (called Sea Monster) has a 4x production, shield, and energy boost (scales with amount of players). Every six hours, Sea Monster factories will send 20% of its drillers at the nearest enemy outpost and send 10% of its drillers to a random outpost it already owns (simulating reinforcements). Person who captures the Sea Monster Queen, or is the last man standing wins.
BROKEN SONARS / CLEAR WATER
Everyone's sonar range is reduced by halfed. Everything else is the same. / Everyone's sonar range is doubled. Everything else is the same.
CONQUEST
The game starts with no dormant outposts (all outposts are evenly divided amongst players); Everyone starts with one mine. All factories start with 40 drillers, and generators start with 10. Queen starts with two specialist hires (The second one has a one hour delay after the first)instead of one. First to 200kg Neptunium wins.
WARRIOR ROYALTY
Game starts like a normal game except all players start with three additional Princesses. In order to attack an enemy outpost or sub, a Queen, King, or Princess must be in that sub, or the sub will be unable to launch. First to 200kg Neptunium wins, or be the last man standing.
CONVERSION
At mines and factories, a new UI is added called "convert." At mines, clicking convert will convert 1kg of Neptunium to 9 drillers. At factories, clicking convert will convert 12 drillers to 1kg neptunium. Everything else is the same.
FLOODED MINES
There are no generators or factories on the map, and no dormant outposts. Everyone starts with the same amount of mines with 100 drillers in each mine. First person to 200kg (can be changed) Neptunium wins, or be the last man standing.
THE GREAT BOULDER
A dormant outpost with (infinite) drillers starts equidistant to all players. Specialist who attack the Boulder are sent back to their nearest outpost at 2x speed. Martyr will only do 10 driller's worth damage to Boulder, but its blast can kill other drillers who are attacking boulder. Mines are disabled. After five days (can be changed by host), person who did most damage to the Great Boulder, or is the last man standing wins.