Routines

New game / restart entry. Runs the front end, then the full new-game initialization, then falls into per-level setup.

Per-level screen setup. It clears the work buffers and play state, draws the playfield border and composes the level's brick field, and renders the tile map. It then draws the lives, level-number, and score readouts. Falls into the per-frame loop.

Top of the per-frame loop (also the loop-back target). While the expand prize is in effect, the loop stages the expanded bat for this frame in the object pool. A grow or shrink animation holds that off, so the grow flag and the shrink flag must both be zero. This stage activates the extension and limits how low the expanded bat may sit. It seeds the extension's position from the bat's. It aims the bat's sprite at the top half of the expanded-bat sprites, and the extension's at the bottom half.

Anti-stuck nudge. Monitors ball A's on-screen position. If ball A stays within 16 pixels of the saved position on both axes for 30 consecutive frames, the nudge fires. The box reaches 15 pixels on one side and 16 on the other. It turns ball A's heading half a turn around to break the stuck rally. When the ball moves out of the box, or the nudge fires, the routine saves the new position and resets the idle counter.

Per-frame subsystem pipeline. Runs each update in the fixed order of the stages below. The end-of-frame state checks come last.

Stage 18: prize-reveal tune sequencer. Once armed it plays the prize-reveal tune one note per frame through the tune player, and stops at the tune's terminator.

End-of-frame state checks. Once the death pause reaches 60 the life is over. With no lives left, play goes to game over. Otherwise play returns to the top of the frame loop, unless an active warp or the level-cleared flag diverts it to the level-advance handler.

While a warp runs, the main loop advances one level per frame until the warp countdown runs out, then clears the warp flag. A warp thus jumps the player forward 1 to 4 levels.

Level cleared. After a pause it awards a level-clear bonus of 100 points per step of the level index level, capped at 2500, then advances the index. An index that reaches 50 or 100 speeds up the rally: it lowers rally_accel_interval by 3, with a floor of 2. At 100 the index also wraps back to 0 at wrap_level_index. Re-enters setup_level for the next level.

Wrap the level index back to 0. The brick-field layouts, spawn cells and wave scripts hold 100 records each, one per level. They therefore repeat from here. The displayed level in the level caption does not restart with it.

Game over. Draws the GAME OVER banner with the double-height printer and plays the game-over tune to its $0D terminator. It then runs the high-score check to test and enter the score. Plays the title tune while it waits for fire, any key or the tune's end, then restarts at the new-game entry.

Wait for restart. Loop the title tune until its terminator, any key, or fire. Any of the three restarts a new game at the new-game entry.