I can vaguely remember a game on the N64, I believe. You were a kid with black hair, and you could also turn into an older version of yourself at will, I think...maybe, anyway. I think there may have been a girl around somewhere as well. It was all classic Japanese sorta design in the setting, but there was funky stuff like lasers too.
And a huge mecha battle. REALLY huge mecha battle that involved flying across a plain while shooting the other mech from the cockpit of yours in first person view. Goddamn awesome. Really, really hard at the same time though.
No idea what it was called at all. Only played it a couple of times. Shame, I'd like to try it again and see if it's easy now.
(Also, first post, hurrah! No more skulking in the background!)