by chrisib
I haven't played many 2-player games, but with 3 players the Hydrans, Orion, and Mechenema have all been contenders.I'm wondering how well the Enlightened would work with two players. The only time I've used them in a game that small was my first time using them and I lost to Exiles (partly due to absolutely abysmal sector draws, but also because I made the mistake of not attacking one turn earlier when I had an opportunity and didn't take it). Their free Wormhole Generator shrine ability is pretty easy to get and means they can turtle amazingly effectively while still retaining the ability to attack.
If you're good/lucky with the Enlightened and can cut your opponent off from most of your sectors and get the wormhole shrines early you can definitely harass your opponent. Jump interceptors through back-doors into their sectors and force them to leave/build ships in their dead-end sectors. If you manage to grab the Cloaking Device (which is iffy, but potentially doable) then you may wind up having a very strong mid-game with this skirmishing tactic. It's likely not the strongest strategy in the game, and there are a lot of "if"s, but it could work.
And just because nobody's mentioned them yet, I'll go and toss humans into consideration for strongest in 1v1 play. Their ability to move 3 ships at a time (combined with avoiding the Syndicate's inability to build dreadnoughts) means they can often bring a larger force to bear against their opponents. Add that to their more flexible economy (2:1 trade is *awesome*) and they're certainly one of the most adaptable races. If you're up against Orion you can play the economy game to take more actions than them to out-maneuver their ships or turtle behind starbases and grab technologies until you can take them head-to-head. Against Hydrans? Use your extra ship movement to hit them hard early on.