I did not play the game that much ( the artstyle and slow movement speed were irritating to me), but the concept is pretty interesting. Going around Mars to collect resources, that you then use to buy new equipment with which you can go to new areas.
At the start, it took me a while to figure out that I had to pick up the pickaxe (it was not really clear that it was there), so I was mashing buttons like crazy trying to get something done. From that point onwards it was pretty clear.
I would recommend that you put in some kind of background music, as it makes the experience a lot better. Also, the sound effects, especially those of breaking glass pots, were a bit high-pitched and where a bit shocking because of the lack of background music.
Although the graphics are certainly not "bad", I would recommend that you try and find or make at léást some more difference in rock formations. All the walls were exactly the same or at the very least só alike that they seemed the same.
The game has a bit of a slow feel, because the character moves so slow. I get that it is an astronaut on Mars and that Mars has a different gravitational field than our planet, but when you compare the walking speed with the breaking speed of the rocks (2 hits), it is absurdly slow.
The space stations were exactly what I would have expected of space stations, so that was very well done, but there is one thing that I thought was a bit weird: Why does the main character walk into the space station while still wearing his suit. Wouldn't there be enough oxygen in the space station for the main character to take off the space suit? I would imagine that walking around in a thick space suit all the time would be very tiring, at the very least, so taking off the suit whenever you safely can, is something most people would do. In fact, real astronauts do not (usually) wear space suits while there are in their space stations. Therefore, I would recommend that you make another sprite for the main character without a space suit on that replaces the main character when he/she is in a space station.
Of course, pointing out flaws and giving both positive and negative feedback, as well as giving suggestions is expected of a reviewer. Just know that me giving you a bit more negative feedback than positive feedback is not personal nor hate speech. Just wanted to make sure I am not misunderstood :D.
Anyway, the basis is there, so it is worth at least 3 stars for me. With a bit of "upgrading" I think it can reach 4 stars. Good luck!