Eh, 1 is a bit rougher than the others but it's still definitely playable. And it's the closest the series ever got to an interesting plot.
Play it for the plot.
I can't believe I'm saying this for an EO game.
For all the shortcomings EO1 has thanks to the improvements on the sequels, It really has the best story in the series. Though for me, my biggest problem with 1 and even 2 is the lack of Battle Speed option, after having it in 3 and 4, its slightly hard to go back.