You can certainly do that, it might work as a warmonger, then you can steal the other techs as you conquor planets. But i think you really need to keep it balanced. i generally keep my reseraching to things that will take less than 5 weeks. (unless i REALLY want something thats at a higher tech level). Even as a warmonger, you'll still need to research industry techs and you'll need better economic improvements to pay for your war machine. I don't think the tech tree was deisgned to keep you on a certain path. its just that most techs in one branch do not depend on those in another branch. I never played Civ IV but in Civ 2 the techs were interdependant, you couldn't get to the end with reseaching everything. what i mean is, if you wanted to get a howitzer you would have needed to find electricity at some point even though a howitzer isnt electrical. GALCIV2 has a tree but its more linear.

Keep in mind this is a VERY complex game especially when you have lots of colonies and lots of ships . It's not dumbed down like a lot of other RTS's . I can recommend 3 things ... Look for strategy threads,use the strategy guild ,read the AAR's in that forum if that is not helping then use the money cheat to keep your empire aflot until you learn the economics of this game which is the hardest part IMO.

Also if you are in a game and you don't like how things are going you can press cntl+N and the galaxy will reset with a new random setup without needing to exit to the main menu. I find this very useful when playing on maps with multiple evil races because if you are surrounded by them on all sides your just asking to lose the game .

GC2 is a turn-based strategy game. It's not exactly going to be a rollercoaster ride from turn one. For me, strategy games become fun when I understand the basic rules and I can plan strategies and try them out to see how they work. If you liked Civ 4, you should like GC2. I think GC2's biggest advantage over Civ 4 is how much you can customize the abilities and appearance of your civilization and ships.

On the medium settings, habitable planets are too sparse for my tastes. Try something like medium size galaxy, abundant stars, common planets, and common habitable planets, against about 5 opponents. "Tough" is the fair level, where all AIs are set to "Intelligent", but you should probably try your first game below that.

There are a few important things to know about the GC2 economy. The first is that factories and labs use up money to create production and research. So building lots of factories and labs causes you to spend money faster. You need to make enough money to fund those factories and labs.

Most of your money will come from taxes, which means you want large populations, a high tax rate, and many market buildings. The difficulty is that raising the tax rate lowers your peoples' morale (AKA approval), and low morale lowers the rate of population growth. Population growth on a planet doubles when its morale is at 100%, and stops when it's below 40%. So one trick is to set taxes low enough to get 100% approval at the beginning of the game when you have a lot of money in the bank. Once that money is used up, then raise taxes to about 50% approval. Also, before the game starts, I recommend picking economy, morale, and population growth abilities.

The tech tree offers a lot of freedom, because you can research anything at any time. I think the most important techs to get early are: impulse drive, universal translator, trade, xeno industrial theory, and advanced computing. Those will cover early planetary development and diplomacy. After that, you need to think up a strategy and research the appropriate techs. Extreme colonization techs can be good if you need them to colonize high quality planets nearby. Or you can go for military techs and conquer planets another civ colonized. The diplomacy line will help you make better deals and stay at peace with your neighbors. The economics, entertainment, and government lines will increase your income. The factory, lab, and asteroid mining lines will increase your output. Or go for influence and take over the galaxy that way. You'll want some balance since each tech is more expensive than the previous tech in its line, and every empire will need a decent economy and production base. But other than that, feel free to ignore some paths and go deep down others.