San Francisco, Jun 22 (IANS): As the search for a missing OceanGate submarine intensifies, an indie game called Iron Lung which is a short tale of piloting a tiny submarine with rudimentary tech through an ocean of blood on an alien moon, has seen a spike in sales.

The indie game developer David Szymanski said that the game was seeing a spike in sales and popularity on his personal Twitter.

"This feels so wrong," he posted on Twitter, along with a graph of the sales that went up after the tourist submarine went missing with five people on board during an expedition to the Titanic's wreckage in the North Atlantic last Sunday.

The game is also being bombarded with positive reviews, one of which reads: "Retroactively based on a true story."

"For those who are interested in Iron Lung but averse to playing the game, YouTuber Markiplier is set to direct and star in a movie adaptation that may be less frightening," reports Polygon.

Meanwhile, the search for the missing tourist submarine entered a critical stage as the dwindling supply of oxygen in the vessel was estimated to run out on Thursday.

The Titan submersible, operated by OceanGate Expeditions, begins each trip with 96 hours of life support.

The search area covers an area twice the size of the US state of Connecticut, and a sub-surface area 4 km deep.