Goblin Runner

 Obstacles 

Two obstacle types are drawn at random from the spawner, one every 2 seconds: 

Floor obstacle — sits on the ground. Jump over it. 

Sky obstacle — hangs above the ground, leaving a gap underneath. Stay on the ground and run through the gap; jumping into it is what kills you. Because the two types ask for opposite reactions, the run is a reading exercise rather than a rhythm one — you cannot jump on a fixed beat and survive. Obstacles are recycled from an object pool (3 instances per type, grown on demand) instead of being created and destroyed, and a despawner trigger off the left edge of the screen returns them to the pool. 

Power-ups 

Power-ups float two units above the floor, so they sit in the arc of a jump rather than in your path. They appear on a randomised timer — one every 5 to 11 seconds — and the two types are drawn with equal odds. Like obstacles, they come from a pool and are returned to it when collected or when they leave the screen. 

Shield —  Absorbs one hit, or expires on its own after 5 seconds — whichever comes first. A glowing aura around the player shows it is up.

Extra life — Adds one life, up to a maximum of three. Each life is shown as an icon in the HUD. | When you hit an obstacle, the shield is spent first and the life only after it. Either way the obstacle shatters and the run continues; the game only ends when both are gone. A spawn coordinator keeps at least half a second between any two spawns, so a power-up and an obstacle never appear on top of each other.