Kaboom was a Bomberman clone that never saw the light of day, one of the infamous Games that weren't.
It got to a fairly developed Alpha stage before Wayne was tempted off to join the Reflections team of Psygnosis. Disk Images of the alpha have been circulated.
A comprehensive history of Kaboom and its perpetual near-release status, including information from people involved in the sound and graphics for the game, can be found in SAM Revival issue 17.
Initially was to be released by Phoenix Software Systems as per the loading screen. Although was (almost) released by FRED Publishing later.