I noticed that the outpost took all my steel so I couldn't use it anywhere else, until I sold it. Perhaps make it so it leaves the steel in your warehouse and then consumes it when you want more space.
As others have mentioned, the room expansion 'upgrade' is actually a downgrade, my thoughts would be to give it something to counter that like a percentage increase in cash or reducing the cost of the other upgrades or spawning power ups like double cash or speed for x amount of seconds.
Just continued a game and it made an ingot immediately when I was saving gold for a luxury watch... It needs to remember what you were making from before you closed it.
"I had to copy and paste the division symbol on level 13 from another website because the division symbol is not available on a standard keyboard. =/"
I just put in "Divide" and it worked. >_<
Nice game... Brains about melted though. You ought to make sure level 1 can't be done without doing something as I have tested due to bordom of not playing. 4.5/5.
There isn't a last weapon as of yet, but it's always fun trying to find out even though i won't get it for about 1 year xD. Great game, i keep saying. Quite addictive. ;) By guessing I've played it about 150 times. Not sure though. Memory isn't good in that region.
The game is brilliant, a few glitches like warping through walls without portals and the same with boxes, not quite enough friction but never mind and also the energy balls area is slightly too big for it's size, but i still enjoyed it
 "Minesweeper World"){kind=icon}
 "Car Crush"){kind=icon}
 "Endless Expansion"){kind=icon}
 "Idle Snake"){kind=icon}
 "Gold City"){kind=icon}
 "Astrox"){kind=icon}
 "PicTune"){kind=icon}
 "loops of zen"){kind=icon}
 "Age of War"){kind=icon}
 "Onslaught2"){kind=icon}
 "Portal: The Flash Version"){kind=icon}
The increased room size doubles your money income.