The game has very hard to run controls. im afraid i do not have three hands to have one hand at wasd, another at lmb and space, and a third hand at my mouse. even with a logitech g502 hero mouse and assigning a key to certain buttons, you really only do that for one button, and it's not easy to use a mouse like that. plus, it uses almost ALL OF MY POOR, POOR CPU AND RAM, I COULD NOT EXIT IT AND OPEN CHROME FOR ANYONE'S SAKE, AND it doesn't even save my progress. basically, really bad deliverance. but amazing game.
i thought lmb was literally l m and b. w a s and d are represented as wasd so it's reasonable to assume that l m and b would be represented as lmb, especially after seeing it shown as lmb. also he could have just said left click. regardless, this does not eliminate the fact that it can run as good as a windows xp runs Skyrim, and it does not save your progress.