Yes, it is true - it can be kinda hard to understand at first. Unfortunately, we didn't have enough time to make a proper tutorial - we barely made it in time :D But we'll definitely keep this in mind!
Our point was that the player has only one knife which he can use. It recharges slowly, but there's no other way to defend yourself. It can be kinda unclear, so I've written it in the game's description :)