Day of Dr. Null (2006)

From the introduction:

He’s waited. He’s schemed. And now, finally, his day has come…
In the first part of this adventure, Fist for a Day, the nefarious Dr Null tries to transfer his mind into the powerful body of the Neutron Fist, but a hero’s mind is swapped into the Fist’s body instead. The hero in the Fist’s body is the only one who knows about the next phase of Dr Null’s plans–he must make his way across town resisting police and even fellow superheroes who think the powerhouse supervillain is on a rampage through downtown.

In the second part, Attack of the Atomic Supermen, Dr Null’s master plan is revealed as he unleashes an army of synthetic super clones in the very heart of the city. It’s a no-holds barred battle royale as police, the National Guard, and just about every superhero wearing a cape fight to defend the city from total destruction.
Day of Dr Null can be played as a stand-alone adventure or it can be combined with Dr Null: Battle on the Bay Bridge and Death of Dr Null to make a complete story arc.

Dr Null: because no situation can’t be made worse with science…