it gets hard really fast, and then there's no stopping them
Kind of drags along...
I played to level 12 and it seemed the game got slower and slower and my mouse clicks often weren't recognized, making it frustrating to continue. Despite that, I found it incredibly easy to shoot all enemies without anyone even coming close to hitting my cube Earth.
Well, the graphics and gameplay were overall good, but their were minor glitches and it was rather easy--so easy I'd call it broken, in fact.
I found that if you got your spreader and rapid fire to level 2, and then just pointed your mouse to one side (the left for me) of the planet, and then spun it while firing, you would fire an almost solid stream of shots which all the enemies would move onto. After that I breezed through the whole game without ever stopping spinning or shooting (except to buy upgrades). Even the last level was a joke, with lvl 3 spreader and 4 rapid fire. I never had to aim, never got hit.
As for glitches, other people have said they bought upgrades but didn't get them; they're likely wrong. When I bought an upgrade the upgrade menu often wouldn't update, so I thought I had lost my money without getting the upgrade. However, if you close the upgrade menu and open it again, you'll see that you have the upgrade. Also, I had a problem with opening the upgrade menu--it frequently wouldn't open and I had to click it several times.
To other players; don't bother buying defense or overgrowth, focus on morale boost and spinner early, then rapid fire and spreader.
Once i've understood the mechanics, I've fond the game far easier. Logically, when you spin, the bullets will spin also, giving you an advantage, the game also got repetitive too fast.
Cool game, but...
The spinning world is amazing, I like the menu, but one thing though... the physics while spinning are off, If I am really spinning the world only, then the missiles I fire off the world shouldn't spin too. It's annoying that it doesn't work that way even though it should.