There seems to be two effects on that image: The "stretching" of the flowers in the lower corner, due to the tilt bringing the corners of the film outside the area of good definition for the lens. There is also quite a lot of light fall off, some of which could be from the enlarging lens being pushed beyond its capability.

An aperture of f:32 seems rather large to me for a tilted wide-angle, I think I would have stopped down to at least f:45 to improve the definition in the corners. Diffraction won't be a visible problem until f:128 at least. It's more important to avoid soft corners, in my opinion...

Next time try tilting the back instead of the front. That way the entire film stays indide the circle of good definition. if using front tilt for this, you should also use front fall to bring the center of the film on the optical axis of the lens. It's amazing how little it can take to tilt the front too much!