Unusual strategies you enjoy

[Anarcomu]

Well, the objective is to have fun. So tune the difficulty at your leisure, but sure, Marathon speed is definitely in your favor.

 

[Alpakinator]

Venice Warmonger.
You will never ever get to control a city outside your capital ; this mean any instant yield is more valuable since you don't get penalized by empire size.
You puppet are also extras compared to other civs' puppet.
Start authority for those juicy yields on kill/city founding/capture. The Great Lighthouse is very strong, allowing your Liburnas to come into contact to cities, bombard, get out.
Then hunt percent-based bonuses because they are extra-valuable for your puppets, which get a native strong percent penalty so any bonuses works double in comparison.

I usually go Artistry second, for the numerous good bonuses :

• -1 unhappiness from urbanization,
• Free Great People Merchant
• +10% culture whilst in golden age
• Additional tourism (you will never get maluses from too much cities, because Venice)

Then of course Imperialism for that sweet sweet +20% to all yields to all cities but the Capital.

And you can use for extra trade routes to send massive production to your capital so you can cram out units, buildings and wonders very quickly.

Cool! I forgot percentage buffs and debuffs always cancel each-other out, never multiply by each-other. So if a Venetian puppet has 50% penalty on everything, and you build Sistine Chapel, then That puppet has only 50% -10% = 40% penalty on culture! I thought it'd be around 50% - (50% * 10%) = 45% penalty. Proof:

22*(100%-50%+10%) = 13.2

Especially strong on non-venetian puppets with 80% penalty.

 

[Alpakinator]

To add to the Venice warmonger strat:
If you have 2 or more Towns, and large GPT, then with Great Merchant you can easily get 10-15k gold on a trade mission. On marathon that means 20-30 free Fustas you can buy in a few turns, which combined with:

• city state bullying,
• conquering cities, trading them for gold and GPT
• Winning wars and getting tons of gold from AI

means even more Fustas.
You can get more than 100 of them like that, meaning easy win. On top of already mentioned insane production you can get from venice in early renaissance (500 + prod), which means 1 Great Galleas per turn even on marathon.

If you want/must play to the long game, Great Galleases can almost get logistics after production due to their Bombardment I default promotion (bomb I -> bomb II -> bomb III -> broadside -> logistics). This gives them a huuuuge advantage, because after upgrading to Frigates and Cruisers they can no longer move after attacking, but with logistics they gain this ability back up!
You "only" need:

• Barracks,
• Armory,
• Teocalli (best from Chichen Itza),
• Military Academy,
• Brandenburg Gate,
• 10, 20, 30 xp from fighting or other sources on stanard/epic/marathon
• not researching Dynamite to be able to keep making galleases.