Here are some additional thoughts

1. Auctions, Don't allow player to use all debt money for this and essentially just borrow against nothing.
• If you want to allow players to be able to borrow money set a maximum based on total value of the company, example if the company is valued at 60,000 let them borrow up to 6,000 for auction ect... Especially in the tighter debt game option.
• Personally I'm against using 100% borrowed money on the auctions, see this as a cheat either way.
2. Game End, This happens rather quickly. The game could be slowly going along having players build their empire. All of a sudden one company buys another. The game quickly sells all companies with-in a fraction of the whole game time usually with in a few minutes it is down to 2-4 companies. (Example 3 companies remain in the game of the original 8 players, the human player is by itself a great company on it's own, however, the AI has one company with 4 of the original companies and the other AI has 3 of the original companies.  Even if the Human player has the best company it can't compete against the remaining two and will loose the game in a matter of a minute or two.)  There should be a sense that you could still pull it off until the very end which there isn't at this point.  Basically, make it possible that one company could be as good or similar to multiple smaller companies merging.
• Limit it to 2 offwold platforms per company even after mergers. If they have more than that the remaining cease to function.
• Don't limit the game to 2 offworld platforms, however, could become all about how many can we build .
• Add a black market option to block take over for a certain period of time, (long enough that next black market is option becomes available for purchase, so you can keep choosing this option but, make it like the others where that increases in cost the more you choose it making this have a cap.
• Add a black market option to inflate stock price of stock by x% as long as you own more than 50% of the stock ownership of the company. (after all if the company is more than 50% you could decide if you want to be bought out or not.)
3. Other Black market suggestions...
• Add more positive black market options such as find new resource deposit, (could offset the underground nuke)
• Add black market option to reduce effects of EMP or cut time in half.
4. Suggestion for game type...
• Territories, when you start the game split the map into sections and have the players auction for a section of the map, later in the game that player could sell building rights to other companies in that territory.
• Along the same point Safe Build Zone game option.  Allow you to "claim" tiles for future build (purchase them essentially) or allow one claim areas x tiles away from your base or something along that point.
5. Complaints/Questions
• Value of a company seems to have not much to do with liquid funds.  In the most recent game, the competing remaining company I could buy out for 1.6 million, and I had 1.4 million in liquid funds on my way to purchase them.  Instead they bought me out prior to that.  In this situation, I had complete ownership in my company and owned 1 share in theirs, they owned the rest of theirs.  So here is my questions...
• How is the value of the company determined?
• How can a company who's value of 1.6 million purchase a company who has liquid assets of 1.4 million plus 1 share in stock in their company when they have no ownership in mine?
• How is stock value determined?  Being the stock value doesn't seem to match 1 tenth of the value of the company, or doesn't seem to reflect dividends or gross income either?
• Claimed tiles can be built on by initial colonies.
• Starting a new game there was a nice area of water, I claimed the tile and I was in route to build, when plop a competing company established it's colony there.  Once a tile is claimed it shouldn't be able to be built on by any other company is my opinion.

So far I like what I see, I hope it continues to improve throughout the process...

1. Additional points...
• AI doesn't want to save resource tiles...  Now this could be by design however, I've noticed they will plop their colony right on top of high levels of a resource and then build 5 tiles away on the resource they just covered up by their colony.
• AI seem to team up on human player even though not on the same team.  I've been playing easy and it's hard to win on easy with 7 AI's as they all seem to focus on the human player.  Again this could be by design being that I seem to take the early lead, however, with the black market being in play that quickly changes with all the sabotage on me .
• Too the above point, possibly give an option of what black market options you want to be available throughout the game such as I want there to be a black market but only want the additional claim tiles to be available.