Devilishly Good and I got to help beta this game and I really enjoyed it (I believe DG did as well but only he can truly vouch for that himself)!
I find the game's concept of meta-game upgrades (upgrading stuff for future missions based on your earnings from previous ones) a neat hook but at the same time kind of annoying that some of those key upgrades would require a LOT of saving up from smaller missions.
Those two non-campaign modes, Survival and Mining are my favorite parts of the game. They both play by basically the same rules with the big difference being how your performance is evaluated. In Survival Mode it is all about how long you can keep your base from blowing up whereas in Mining Mode, who cares how long you last, it is more important to judge you by how much ore you could mine before your base is finally overrun. Oh, and if not already obvious, what was meant by Fixed or Random maps in these two survival modes of play is whether the location of the asteroids in the game are always in the same places or randomly mixed up.