Known defects

A player good enough to clear all 100 levels may never get to. Before they do, the playfield can freeze, or the ball can fall into a loop it cannot leave on its own.

Wedge, shuttle, orbit and skim trap the ball in a path it cannot leave. The ball moves in sub-pixel steps. Each axis moves one pixel only when its own count fills up. Every bounce empties both counts and leaves the ball where it is. A ball that bounces before its slow axis moves a pixel therefore travels on one axis only.

A bounce depends only on the ball's heading and on what it hits. A ball that comes back to a place at a heading it had there before repeats its path for good. The anti-stuck nudge turns ball A around after 30 frames within 16 pixels of where it was on both axes. The next bounce undoes the turn, because a heading and its opposite leave a surface at the same heading.

A trapped ball never returns to the bat. Destructible bricks off its path stay out of reach. The level cannot clear while any remain. With none left, the level ends late.

The ball meets the face of a golden brick almost along the face. It bounces off the face each time it probes ahead, and never moves away from it.

Each bounce scores. Only a bat bounce resets the combo. The score climbs without end.

A diagonal ball meets an inside corner of golden bricks, where the cell beside it and the cell ahead of it both block. A corner sends a diagonal ball straight back along its line. With such a corner at each end, the ball runs between them for good.

The ball bounces among golden bricks and borders along a path of three or more legs. It comes back to where it started at the heading it started with. It then repeats the path for good. Nothing on the path ever changes.

The ball runs along just under the top border at a heading close to the horizontal. Each time it probes ahead, it also tests the border cell above it, finds it solid and bounces. The bounce is silent and scores nothing.

Play with the bat on the right, so the wall runs down the left edge. Clear the bricks from the bottom-left corner and let the ball reach the corner cell.

The game redraws only the cells whose dirty counter is set. A terminator ends the scan. The terminator sits in the bottom-left corner cell. That cell never changes in normal play. A ball drawn there overwrites the terminator.

Without the terminator, the redraw runs past the end of the dirty counters. It sprays graphics over memory. Bands of the screen change color. The redraw never draws parts of the playfield again. Play and the score go on underneath. The damage lasts until the next level starts.

A level ends when every brick slot is empty or holds a golden brick at rest. The check for this skips a golden brick only when it shows its plain face. A golden brick flashes when the ball hits it. It also twinkles at random. In either case the check takes it for a brick still to break.

The level ends at the first check that finds every golden brick at rest. A ball that bounces among golden bricks therefore pushes the end back, for as long as it stays there.

When two bombs lie next to each other and the ball takes one, its blast clears the eight bricks around it. The other bomb shatters like a plain brick and never detonates.

An orb that catches the ball chews it, then spits it out, and the ball slides back toward the bat. On the way its animation runs past its last frame and never stops. The orb then wears frames of the comet and then of the hive.

The drift ends when the ball reaches the bat's losing edge. There the player loses the ball.

A key pressed while the front end is on screen leaves a speck in the visor's first frame. It stays until the player resets the machine.

The ROM stores the last key it accepts in LAST-K. The game keeps a byte of the visor's sprite at the same address. It never copies the sprite in again.

The missile launch tests fire in a value it does not choose itself. Under direct control, and under the inertia option while the bat stands still, that value is the controls.

While the bat moves under the inertia option, it is a step from the inertia speed ramp. During the bat freeze, it is the freeze timer. Neither ever holds the fire bit, so the missile does not launch.

During the bee's sting, it is whatever the object manager used last. The launch then follows that value, not the fire key.