Doblons is another simplistic 2d shooter game that is incredibly addictive! Despite being very basic to look at its progression system is quite in depth, giving you the option to upgrade and design your boat in several different ways.
You start off as a very basic boat with 2 side cannons and the hope that eventually you can be a hugely feared battleship amongst the server. The game is very fun and because of the different available variations you can play a different way every time until you find what works best for you. You sail the seas collecting the coloured orbs which passively spawn or killing enemy ships in order to gain experience and gold which can be used to upgrade your own boat. There are stats that you can put points into for the cost of coins at the top left of your screen, and once you fill the xp bar you can add a gadget to your boat. In my own experience I found putting max movement speed with a strong hull and a battering ram to be incredibly entertaining.
In this game you can use either the WASD or arrow keys to navigate and either left click or the space bar to fire your cannons. The f key is also used to fire aimed shots at the cost of coins.