Enjoyable, but...
Rather enjoyable game. Nice time-waster. However, a few points I'd like to address.
1) Apparently, the 'expense' for "block recreation" increases per your total. I presently have 898 blocks. Producing one drops the total down to 882. Perhaps I wasn't observant enough to notice this when the total was lower. I'm not sure what purpose this serves, regardless. beyond just decreasing the amount of available blocks for hoarders. I'll also admit I panicked a bit when the 999 rolled over into the 100's -- I'd thought I'd lost them.
2) Picking a larger music scheme could never hurt. Kudos on those tracks already present.
3) Someone's already mentioned using labels for the recipes. Also having a way to pull up both the Recipe and Construct screen might be nifty. Perhaps one nudging the other over? :)
4) While the overarching goal of engine-building is nice, there's not much incentive to do much else. If you decide on a sequel, why not other characters or bosses? :x Using the drill to attack weakpoints could be swell. Perhaps using minerals left over for special items and what not? Sea gulls, sea snakes, anemones, etc. ;o Just a thought.
I really have enjoyed the game -- still playing. Haven't gotten _too_ far, but, it's keeping me interested. Kudos kudos kudos!