Immediately feels pretty nice, appreciate the speedup button greatly, and the 2x bonus for full clearing a planet is nice. The basic gameplay loop is definitely there, reminds me of To the Core, which I imagine was probably an inspiration here.
A few planets later, I can't help but notice there seems to be no real incentive to linger on any of them. I clear a planet and that gives me enough to just buy the next planet, which gives more money, and one clear gives enough for the next planet...fewer planets that you spent longer at would feel much more nicely paced. The 4th planet only took me 2 quick rounds of digging to the center for the high-value materials to afford the next planet, and that's only because I got unlucky with ore spawns on the first round. My only upgrade is energy level 5, for context.
Yeah, the loop of constantly interrupting the fun part of gameplay to go back to the galaxy menu and buy the next planet gets pretty annoying, should definitely have fewer planets that are harder to buy, I think, so the player can actually focus on the digging part for longer at a time. ...Oh, already at the first prestige.
Prestige feels nice, a good, chunky leap in power, feels very satisfying to play. ...Definitely confirms how annoying the loop is of going back to the galaxy menu, clicking next until the green number turns red, then clicking back, buy, and play, though. Maybe planet automation would work, automatically buy the highest planet the player can afford and place them there between rounds? Just give it a toggle so the player can save their money if they want to, but buying planets as soon as you can seems to be optimal, so automation for it would be nice. Let me buy some upgrades and see if any automation shows up.
Running into another issue that becomes apparent at around prestige level 4 for me. When you reach a certain size, the individual chunks of the planet become so small you can't see where the remaining ore is. Combined with the increasingly high energy levels, this results in me circling around nipping at the last pixelated remnants of the planet trying to get the full clear for that sweet 2x bonus. I'm not a developer, so take this with a grain of salt, but the easiest fix I can think of off the top of my head for this is to only require a percentage of the ore to be collected starting at some point before the rest are harvested for you. Something like, when you've got 98% of it, the last remaining pixels are cleared automatically since the player can't actually see them anymore. And yes, I do know there's a button to abort the level, but I want the 2x full clear bonus, being forced to abort the level constantly would suck.
At prestige level six now, I'm so large that I can barely see the first asteroid anymore. And since I'm forced to start on it, I often miss the asteroid entirely since my mouse was placed on the "Play" button to start the level, and with my scale (and thus speed) being so high, I quickly soar off into the distance. It's getting harder and harder to see where the asteroid actually is in order to steer myself back towards it, it's naught but a spec now. Could probably use some sort of level borders that scale with the player's size to remedy this so you can visually see the area the planet should be in. Something simple like just a red ring would work fine, it doesn't even need to block movement, just be visible to indicate where the asteroid is.
Ending at prestige level 6, and the energy upgrade at level 51. Could really use a "buy max" option for upgrades, I had to actually click it 50 times. Never unlocked any other upgrades though, so obviously no automation. Anyway, hope this feed back can be useful to the dev, I'd definitely pay, like...$5 for an expanded, polished version of this. $10 if it's really good and has a good amount of content.