Do you have some ideas for me how to use that potential?
Check out some simple clicker games on mobile. Observe the main game loop, UI design, visual cues, sound feedback. You don't have to copy them with 100% accuracy, just get the basic idea and mechanics, then prototype it. Eventually you will end up with many small prototypes and think of combining some of them enough to make a small game or minimum viable product (MVP).
In your game, your primary loop is probably the space travel because you spend more time in it the more you upgrade the fuel. Mining/clicker mechanic is the secondary loop for obtaining resources. What you would want is to make the primary loop feel more fun, lasts longer, and happening frequently than secondary loop.
I got few ideas to add up to your primary loop.
- Discover new planet after travelling a certain distance - You can see this in common runner games with distance meter at top screen. Unlock something after reaching a milestone, achievement, new item, new upgrades, etc. In this case, the planet can grant resources and materials.
- Random events and encounters - As you travel, you might find an abandoned ship with resources, or found a rare asteroid you can mine for rare ores, or found a fellow astro-miner to help you on your next mining. Just a pop-up message with options.
After you finalize the whole idea, you can polish the game then focus on contents.
Sorry for replying that late:
I thank you a lot for that feedback and will think about it in close future. I will definitely rework the primary loop and think about and think about turning the secondary mining loop into something a bit more optional maybe.
I like the idea of random events. I surely can realize that somehow and will think about a range of possible encounters (maybe some negative ones which you can avoid more with some upgrades). About the discovery over a certain distance. This will probably take some more effort to realize it but I will keep it on my idea list.