Stickman Kombat 2D is a proper 2D fighter rather than a button-mash brawler: it has blocks, uppercuts, two distinct special moves, aerial strikes and a combo system that continues if you time the next attack correctly.
Two players share one keyboard, which is where the depth pays off — against a friend who also knows the block button, matches become genuine.
Press attack at the right moment during the previous one to continue the chain. Mashing breaks the timing rather than extending it.
Yes — Player 1 on W A S D with F and G, Player 2 on I J K L with the colon and quote keys.
Hold S. It's the single most useful thing new players overlook.