I'm not exactly sure what to make of Ecks Versus Sever. The game seems like a major technological achievement, being one of the first games to get polygons onto the Game Boy Advance. Yet it also seems like a dinosaur, playing and looking like Doom, and using, of all things, a password save. The password save especially threw me off. I don't think I've seen a game that used password saves since the NES days.
Undoubtedly, Ecks Versus Sever is a very competent FPS despite being hampered by a very tiny view screen, barely serviceable controls, and limited 3-D rendering hardware. It has a uniquely conceived design premise based on the two playable perspectives of its opposing spy protagonists, Ecks (emotionally-scared father where the death of his family continues to haunt him) and Sever (heartless femme fatale who born and raised to kill).
According to ESRB, this game contains: Violence