HORROR OF MEMORY: The Boston Marathon: Terror on the Streets instruction manual.

A shocking new video game depicting the Boston Marathon bombings has surfaced online.

Hosted on the website Lolokaust.com, The Boston Marathon: Terror on the Streets was released one week after the Boston tragedy.

"Tired of watching the Boston Marathon bombings on TV?" a preview for the game states.

"Well now you can live it. It's a game!"

The game features crudely constructed images that hold true to the event, including a man in a wheelchair who has had his legs blown off.

Edith Cowan University Associate Professor Mark McMahon, who coordinates the Game Design and Culture course, says that violence in video games in nothing new, but an "untimely and tasteless joke."

"There's probably nothing that is illegal in it in terms of the level of graphic violence. It's how recent it is to the Boston bombings that makes it offensive by most people's standards," Associate Professor McMahon said.

The game comes with a full online manual which instructs players to avoid hazards "to reach the finish line with all [their] limbs intact."

According to the manual, the hazards include "pressure cookers that have been weaponized into IEDs [improvised explosive devices]" which are "commonly used by Muslim terrorists but also extreme right-wing conservatives."

Cartoon crowds, including "suspicious people", cheer players on as they run the race.

Instead of 'game over', players who fail to avoid the hazards receive the message, "You got f..ked up! Better luck next year!" accompanied by a cartoon image of a man in a wheelchair with his legs blown off.

While controversial, Associate Professor McMahon says it would be difficult for anyone to feel a legal obligation to remove it from the internet.

"They've been quite clever about this. There's tasteless humour, but they're not actually putting you into the role of a terrorist; they're not saying [this is] good."

The game's creators have concealed their identities by using the aliases CMCW and Smileycythe.