A nice take on The Swapper theme there, clean and simple, but it works well. I had some problems with the controls, could be more precise, as I frequently bumped my dead clone and misaligned it and had to start over, which was not possible due to limited lives being a thing.
There could also be a button to kill the player instantly instead of making them wait for the oxygen to run out.
Overall, great work, it's a lot of game for 48 hours!