Browser Game: Dirk Valentine, Boiler-Commando

Armed with a cannon that shoots chains and an awesome green hat, Dirk Valentine is charged with taking on Baron Battenberg and his nefarious steam-powered machines in Dirk Valentine and the Fortress of Steam.

I'm a sucker for steampunk -- maybe it's the old-timey charm of boiler-driven zeppelins, or dials and pressure valves on absolutely everything.

Dirk Valentine and the Fortress of Steam [Nitrome]