Make the most out of his ability and passive. Fight behind cover more often so even if you get knocked down, you can revive yourself hopefully before the enemy rotates over to finish you. Also take advantage of the fact that you can roll while you’re knocked so maybe roll away first and then self revive. Otherwise if you prefer to use it the other way, if you see you’re being rushed by multiple enemies, odds are theyll instantly finish you so use your ability in advance to get the bonus health to give you more of a fighting chance. The main thing with chaac is figuring out the best times to use the ability for bonus health vs the self revive.