Wait, why is your velocity in the wrong direction? You're right that you need to add a whole hell of a lot of horizontal velocity to reach orbit, but you do have ~400 meters per second of horizontal velocity borrowed from the surface rotation of the Earth. You're not going the wrong direction -- there's nothing you need to counter-act. You just need your 2nd stage (assuming we count the initial throw as a 1st stage) to provide all that velocity. The fuel you need to do that was launched up with you. What's the problem? It's a hell of a lot easier than the way we do it now.
> How do you ... survive forces involved
Yes, that is the real problem.
> The projectile has a carp ton of angular momentum after release
No, the centrifuge has a crap ton of angular momentum, some of which is converted to linear momentum in the projectile upon release.