Yes I could play a few mp4 files This phone is not able to recognise mp4 files
placed in the directories created by non MAX mediums. Procedure I could find is, first go to Multimedia->Camera->External album
then use create to create one directory and save it. Then connect your phone to PC and copy your mp4 files to this directory.
File video size supported is 176x144 (QCIF) . Hope this helps