Aye, I enjoyed Dying Light. Good, open world apocalypse game.
Yes, in Rebel Galaxy, you can buy bigger ships. Right now, I have a heavy frigate with some pretty serious firepower. As you get better components, weapons, and ships, the risk factors for each mission adjust accordingly. In other words, say you see a mission that is available, but it might say "Risk: Very High". That's because you have a ship that might not be suited to the task. Sometimes, all it takes is purchasing better armor, equipment, and weapons, and the risk factor might drop to "average" or even "low".
You can go mining for minerals, or scavenging for materials. You can do trading runs, perhaps even smuggling runs. You can collect bounties. Loyalties can change. Need a little extra muscle? Hire a mercenary. The one I have right now is bad ass. She has a gunship outfitted with capital class weaponry. You can go on dead drop runs, liberate outposts, hunt down pirate lords, quell invasions, all to make money so you can upgrade your current ship or get a new one. And when you buy a new ship, your old equipment carries over with you.
Of course, there is the main campaign you can play at your leisure. If the next stage of the campaign has a risk factor that might be too high, do some of the missions on the mission boards to build up money to improve your ship to drop the risk factors. The further out into the galaxy you go, the weapons, equipment and ships get better, as does the money... the the tougher some of the missions become.
This game is a great way to just pass the day. I love that my job as a musician allows me quality time with my favorite pasttime... video games, especially open world sanbox titles like this one. IIRC, the game was pretty cheap. I think I got it for 19 bucks... maybe a little less. It's a big game for a low price tag.... kinda like how State of Decay on Xbox 360 was. (Open world zombie apocalypse survival simulator... or as I call it, a zombopocalypsulator!

) Big game, small price tag... and well worth the money.