Not bad, but need more polish
From a playability perspective, what's the point of running back to the base for every couple minutes of mining? The trip back and forth takes most of the time in the game, and there's nothing fun about it.
The exploration is where the fun is, maybe you should work on ways to make it easier to refuel and/or increase the size of the energy tanks.
There's potential for a pretty fun game in there somewhere.
Not Bad...
This seems almost like a copy of Mega Miner from Newgrounds, which was way better done, it had metals, more variety of collectibles, more upgrades, and altogether more polish. And it did not seem as slow paced as this game. I played it to the end, unlike this one which bored me very quickly. If you are going to copy a game, at least do it well.
fatal flaw
this game is very long and with no mute option the music can become very annoying
can't build anything!
How does one build stuff? I click on the build icon and select the rock wall and a green rectangle shows around my digger machine, but no matter if I hold the action key (E), press the space bar, or click on build, NOTHING happens. I even tried clearing a larger area around where I wish to build and still nothing! I noticed that if I am outside my building area, the rectangle becomes red, so at least that part works to indicate one is beyond the build area. But when it is a green rectangle and I have the required materials for building, why can I not build? Frustrating. Otherwise, a fun game, but as others have said, rather slow.
at first i thought this was going to be great. but after dragging stone around the research grid for awhile.. and seeing nothing but red whenever i tried to build stuff that i had the mats for.. i decided.. the game was too unintuitive to deserve my time.