Since the OP asked and I have experience with both games… I’ll compare Sins to Imperium Glactica 2 and then offer a more complete review below.
The biggest difference between Sins and IG2 is that Sins is more focused in everything. In IG2 fights can occur anywhere and if you had just slightly slower engines than the enemy they could pretty much avoid you forever.
In Sins all fights occur at planet gravity wells. In between the stars are star lanes of some sort. When ships are on those lanes they are not attackable or commandable.
Research is another good example of this. I think IG2 had 4 research trees with tons of options in each. In Sins there are really just 2 and 1 that increases your max fleet size. There is probably 60 or 70 techs to research in Sins compared to god knows how many in IG2.
As previously mentioned Diplomacy is largely follows this same idea. In IG2 you had tons of options for race relations, in Sins AI give you missions like “Give me credits” and in exchange you increase faction with them.
The final thing to mention is that in Sins you can’t design your own ships, a feature I’ve always loved.
So the review section…
Sins is billed as a 4xRTS. 4x for the uneducated is eXplore, eXpand, eXploit and eXterminate. All of the Civilization and Master of Orion games fall into this category. What is boils down to long games with lots of options.
Sins falls into this pretty good. You stat the game with 1 planet and 1 frigate factory and 2 or 3 star lanes to unexplored planets. By the end of the game have access to 6 frigs, 5 cruisers, and 5 capital ships but right now all you can build are colonizers and recon ships and one free capital ship.
There are three resources in the game. Crystal, metal, and money. Money is gained through taxes on planet population and crystal and metal are gained by mining. Your starting system always has 2 metal resources and 1 crystal resource.
This brings me to the first thing I really like about Sins. Everything is very easy to keep track of. If you click on your planet, even while zoomed out to system view, you can order all three of these resource structures built in 4 clicks. You can upgrade your planet in 2. The majority of the things you need to do in game are easily handled and cleanly presented and once you have a planet established you very rarely have to go back.
The only time you can’t really use these system management features are when you are actually placing structers, such as research buildings. Speaking of research… Research is broken down into two trees. This is true for all three races though they are called different things. I believe the Advent calls them Harmony and hostility. Basically peace techs that improve planets and give you building and war techs that give you access new ships and better weapons.
All research is handled from the research screen and once again it is very easy to see what you have access to and what you are missing to get it. If you are missing crystal the icon is grayed out and by mousing over it you can see how much more you need to research it. One nice feature I figured I’d throw in is that as soon as you order your construction ships to build a research facility you can queue the tech for research. This saves you the trouble of caring when the building is done and instead lets you get back to the fight.
During the expanding phase of the game you generally have to wipe out groups of NPCs to take over a planet. The better the planet, the more defenders. This keeps the game from being a flat out mad rush in the beginning and forces you to figure out if you want to dedicate a bunch of resources to take over that terrain planet or quickly grab that dead asteroid for the mining…
Once the expand part is over, things general move into the extermination phase. All races start of at war (unless you have a team game) so you and the computer will always open fire on each other until you gain enough faction to be their friend and as far as I can tell there are really no ramifications. In the early game you really don’t have enough fire power to cause too much damage to an enemy before they can respond and destroy your fleet so things are generally a border war for a while.
When everyone grows tired of the border war giant fleets are produced and the real war ensues. Unfortunately, the options for ships feel pretty limited. All three races have the same basic designs. Recon ship that is cheap, basic combat ship, Long range high damage low health ship, support ship, carrier ship for fighters and bombers, anti fighter and bomber ship, large combat ship, and planet siege ship.
I don’t know how creative people will/can get with the fleets since all the races follow the same design. I figure the majority of the time it will be tons of small combat ships, handful of anti fighters and several large combat ships. I could be wrong though.
That pretty much sums it up. I don’t like RTS games very much because I loose track of units, research, and even cities. Sins makes it easy because you can always zoom out to system view and see which planets you own and where your ships are. If you think “Didn’t I have a recon ship?” you can actually search through your assets and track it down.
Sins is a good game, I played an easy game against a computer on a small random map that lasted a couple of hours and then a 5 hour game with a friend on a 3 star map. Medium difficulty is pretty easy and I haven’t played on hard yet so that should be interesting.
I say it is a good buy.