I primarily made this as a movement game rather than a combat one. I think to balance time I should have made it so that instead of locking the levels you have completed, it rather made it so that only your best time of the level would add to the extra time. Enemies having 3-5 HP is a brilliant suggestion! I could have then made it so that, like speed, it scales with how many upgrades you have in health. Thanks for the feedback!