Curveball

Your blue paddle is at the near end of the tunnel; the red one is at the far end. The mouse (or a finger dragged on the playfield) moves your paddle — it eases two thirds of the way toward the pointer every frame, so it lags a little on purpose. Click or tap while the ball is on your paddle to serve.

Spin is the whole game. A served or returned ball leaves your paddle with no sideways speed at all. Everything sideways comes from curve, and curve comes from how fast your paddle was moving at the instant of contact:

curve = −paddle speed / curveAmount

Each frame the ball's velocity gains the current curve, and the curve itself decays by a factor of 1.004. Pull the paddle to one side of the incoming ball and sweep it across as you hit, and the ball will bend far enough down the tunnel to leave the opponent standing.

Scoring

• 100 for every return, dropping by 10 each time.
• 50 Curve Bonus, dropping by 5 — awarded when the curve on either axis clears its threshold.
• 150 Super Curve Bonus, dropping by 15 — both axes curving hard at once.
• 100 Accuracy Bonus, dropping by 10 — strike the ball inside the 14×10 sweet spot at the centre of your paddle.
• A time bonus starts each level at 3000 and falls by 25 every 11 frames the ball is in flight — about 44 seconds to zero. Whatever is left is banked when you win the level.

Lives and levels

The opponent has 3 lives per level; you have 5 for the entire game, and they are never replenished. Ten levels: the ball speeds up from 2 to 6 units a frame, the curve divisor tightens from 25 to 10 (so spin gets 2.5× sharper) and the opponent's lag constant falls from 17 to 1.

A warning inherited from the original: at levels 9 and 10 the opponent's lag constant reaches 2 and then 1, and a constant of 1 makes it snap exactly onto the ball every frame. It cannot miss. The original had no win screen and no level cap either — it was a game about how far you got, and the far end of its own difficulty ramp is a wall. This port reproduces that rather than quietly fixing it.