One of the better games for PSP
I'll be honest: initially, I only wanted to play this because it is developed by the same people who made Infinite Space for DS, but after three chapters into the game, I can finally say I recommend this game.
I cannot comment much on the story due to my limited Japanese, apart from the fact I can understand where the comparison to Evangelion came from. I won't outright say this is a clone of Evangelion, though; if anything, I believe the developers revisit such story elements on purpose, considering their previous work in IS. Whether it is a good thing or not is for you to decide.
Next, the graphics. I'll say this is one of two strong points of this game. The game is full of animated cutscenes, all of which are done well (they're done by Satelight, by the way). The character portraits don't have blinking or lip-movement animations, but they are animated smoothly when changing expressions. The environment looks bland, unfortunately, but considering the nature of the game, I'll say it is not much of a bother. The enemies and mecha models look good, though.
As for the music, while I don't like the entirety of them, most of the tracks are awesome and fit the game's atmosphere well. The OP is also sung by FictionJunction, which is a plus.
In terms of system, the game is relatively simple since it -mostly- done in beat-em-up style. What makes the game challenging, however, is the fact that you need to know when to dodge and guard. This is especially true in Annihilation (mecha) Mode, since you can't recover your health. The game also comes with three difficulties you can choose, depending on how you want to enjoy the game.
My overall verdict? This game is worth getting, if you like dark stories...or if you don't mind about the story at all. Apart from an element of the game that requires a bit of understanding in Japanese, this game is otherwise import-friendly.