SPEHS is a 2D exploration and spaceship building game with endless ship customization options and a massive open world environment. You can download the in-development version of the game for free here.
Spehs has been in development since 2015 and it is currently in a pre-alpha state. Most of the core features are implemented, but the game is still full of bugs. Development will be slow because this is a free time project. You can follow the progress from the blog.
Spehs is a sandbox game where you build a spaceship, explore the universe, collect resources, fight against enemy factions and complete missions to gain allies. The playable universe is so big that it's practically infinite. There are 3 playable races: Human, Pragux and Prahian. Each race is divided into factions. The ship editor provides an endless amount of customization. You can build ships specifically for your playstyle and even share them with other players.