As a child living in Singapore in the 60's I spent some time in the British Military Hospital. There were still bullet holes in the walls from where the Japanese had walked along the line of beds and shot dead all the patients.
A good book I read later was 'You'll Die in Singapore' written I seem to remember by an Australian soldier who lived through the invasion.
Fiolar, you're right about the expectation of a seabourne invasion. We were looking the wrong way. The big gun implacements I visited as a child were all facing out to sea.
Gary