One way to fix this would be to use the existing code until the ship gets within a certain distance of the wall, and then use a line intersection test to see if any of the lines of the ship intersect with lines in the wall. This would probably require a line cache for the walls to be fast enough. Explosions have always had odd effects depending on the exact location and velocity of ships that encounter them. If you hit a treasure really fast, for example, you fly though the explosion and it actually accelerates you in the direction you were going. If you are stationary you get a normal amount of push, but if you are drifting slightly in the direction of the explosion the force is much stronger because you are carried in the wave of the particles for a longer time.
Balls bounce on center rather than on edge.
This would probably be easy to fix, but it would change a lot of ball runs significantly. Fixing this would also change treasure runs. Rumor has it that sliding radar is broken in the Win NT client. The client will request a display size larger than 1024x1024 with high scaleFactors. Trivial to fix.