What does the constant bombardment of gas molecules against the inside walls of a container produce?

It's pressure.

The constant bombardment of gas molecules against the inside walls of a container produces pressure on the walls; gas pressure results from the collision of these particles on the walls at different velocities. This is known as the kinetic theory of gases. A gas is composed of a large number of submicroscopic particles (atoms or molecules) that are in constant and random motion through the air.

As these molecules bounce around within the container, the energy is contained inside, and the pressure builds. The macroscopic properties of gases include volume, thermal conductivity, temperature, viscosity, and pressure.