Ninja the Game

The first lessons in class we had to come up with a game idea. My idea was to mak a ninja stealth game. In the end I made somethig simular.
In my game: 'Ninja the game' you are a ninja. Your goal is to reach the end of each level. But there are guards who stop you. Fight or sneak behind each guard and get the golden ninja star at the end of each level. There is a menu, a tutorial level and a normal level. There are 4 different pickups:
Health (gives the player lives),
keys (open stone doors),
tutorial pickups (explain more to the player) and
gold stars (make the level end).

Controls are:
Aim with the mouse
W or forward arrow: walk forwards
S or back arrow: walk backwards
LCtrl: for sneaking
LShift: for running
E pressed: for attacking
Your ability is to phase through white walls.