The game sees you control a winged, flying version of the m-velope we know and love from Gmail, flying out of a box on the crater of some moon.
Suddenly it's faced by a combination of objects including rocks, spiky things, and what can only be described as a grey can of spam, all flying at you.
The final end boss is a dastardly bird cage filled with m-velopes, with long arms and spikes at the end to poke you with.
But he said it was also a personal project which he did to learn and play with HTML5, a new version of the HTML standard which negates the need for plug-ins such as Flash.
"I learn better through mistakes so without apology, here it is -- the good, the bad and the ugly," says Truong. "It's not perfect but I know it's progress."
Google employees are encouraged to spend 20 per cent of their times on personal projects like these, one of which was responsible for the creation of Gmail.
Truong said Gmail had solved problems such as poor latency, worthless spam filtering, reliance on folder structures and the constant need to delete email.
"It's easy to take for granted our Ajax-driven interfaces, practically unlimited inbox capacities and search-engine powered interactions with our emails," Truong said, "and so, for this reason, I felt a little celebration of how far we've come was in order (via a doodle)."
"There are still many things I would improve about Gmail and I still expect the product to grow and surprise me with an even faster and more intuitive experience."
Be warned that the game will be choppy if you haven't got an up to date browser, and is particularly prone to crashing.