I think your game idea is fun! I have some suggestions to make it easier: first is to make the rotation just as the keyboard is pressed (no "gliding" rotation), second is to make the ship has a health bar. So instead of directly game over if the speed is above 5 m/s, the damage to the ship will be bigger as the ship land faster. this way the game will end if the health is 0. To make it more fun, there can also be coins, or some health pick up to restore the ship health.