Doblons.io starts off with a player getting a tiny level 1 ship and starting to collect titular doblons in order to level it up. Unlike previous games, the racer driftin.io, there are no starting classes and everyone's ship is the same at first. However, this is offset by the extensive customization options, as there are 8 stats in any possible order through simply investing doblons into them, while every level-up provides an option to install one of several mutually exclusive upgrades onto a ship's front, sides, deck or rear.
Thus, some players may opt to fill their ship's deck with auto-cannon turrets and add even more side, front and rear cannons to belch lead in all directions: others would rather install scatter cannons and gatling turrets to pepper their enemies with low-damage, yet practically inescapable bullets. Others may forgo ranged combat entirely and install a battering ram instead, replacing their side cannons with rows of oars to get unrivalled speed, and getting a rudder to turn slightly faster. Others still opt for a mine layer at the rear as a significant part of their strategy.
Players' levels are ordinarily capped at 75: afterwards, any doblons they collect after this can either be shot out in more difficult engagements through pressing F, or to purchase up to three AI-controlled allies: from humble mine layer ships to stronger Battleships and a singular Man-of-War. Nothing stops a player from investing in such allies earlier, though, and some simply buy cheap fishing boats at the start to collect doblons faster. The downside is that a player who destroys one such ship gets the amount of doblons equivalent to its cost, which is especially easy with the fragile fishing boats.
Still, the daring and/or bored high-level players may instead opt to tackle the boss ship. There's always one present on the server, it's level 85 at least, and it has the kind of size and upgrades that are unavailable to players (i.e. five rows of oars and extremely large mines for MG Masterov boss.) Defeating it raises the lucky's player level cap by 10 as well; another boss will soon spawn in to replace it, so this can be potentially repeated. Of course, losing, whether to a boss, or another player, sends one all the way down to level 1, with only a fraction of doblons they invested into their previous character to sweeten the bitter pill.