• The AIs you are playing against have an AI Alert value, which you can see, that increases every time something particularly interesting happens (usually when you destroy something major). The main effect of this number getting higher is that the AIs will send larger waves of ships to attack you. There isn't any single point where surviving and winning suddenly becomes impossible, but basically the most important dynamic of long-term strategy in the game is evaluating how much resources are worth to you and whether they are worth the increase in AI Alert in order to capture and secure. At moderate and high difficulty levels, games can become unwinable if you destroy everything you can without prejudice, at which point you realize that what you did was dumb, and try again (in a new game, probably).

• You can save any time, create as many saves as you want, and then go back at any time. Experimenting is easy. In my experience, it has been somewhat common to send my main fleet into enemy systems to see if it can kill something, fail and get driven back with heavy losses, and then going back to my save file to try something different.

• Throughout the game, science labs produce knowledge, but a science lab can only gain a certain amount of knowledge from a system, so knowledge becomes a very limited resource. You then use the knowledge points to unlock various things, most of which are simply the capability to build new and better ships and structures. There are so many different things you can unlock and in the end so little knowledge that you cannot do anything remotely close to unlocking every possible thing within a game. The ships and structures you choose greatly affect the way you can fight your battles, especially at higher difficulty levels and in games with fancier ship types around.

Sorry nobody responded until the sale had ended. It is a great game, though, so if you enjoy RTS-like games, I'd still consider picking it up.