Yes. Valves aren't suddenly either "open" or "closed" They spend much
of their time in a partly-open state. The behaviour during this time,
and how fast they move, is important to valve design. This is
particularly important for engines with large valves -- gasflow through
these at low gasglows can be quite poor. A smaller opening for these
over at least part of the stroke can give a useful increase in
low-speed torque on what would otherwise be a very "peaky" engine.

There are two techniques to this. One is an axially sliding camshaft
with conical profiles on the cams. This allows great control of
profile, but it also requires a narrow cam follower face and so
accelerates wear.   Another technique is for a twin-camshaft engine to
have identical profiles throughout, but to vary the relative timing of
the inlet and exhaust cams, and thus the crucial value of their overlap
time.