Redline Apex — A braking-distance puzzle on a race track

What is Redline Apex — A braking-distance puzzle on a race track

Redline Apex looks like a racing game and behaves like a spreadsheet. Your car sits on a strip of numbered track segments and carries a gear from 1 to 5. Choosing a gear does not set a speed, it moves you exactly that many segments at once, with nothing to react to. Nothing is timed and nothing is twitchy, so the board waits as long as you like. What makes it hard is that you may only change gear by one step per move, which means the distance you will travel three moves from now is already mostly decided by the gear you are holding today.

Corners are the constraint. Each corner segment carries a limit, and if your gear is higher than the limit of any segment you cross, not just the one you land on, the car spins: it stops there, drops to gear 1 and costs you two extra moves. Cyan boost pads work the other way, handing you a free gear and eighty points, but only if you land exactly on one. Every circuit ships with a par, the true minimum number of moves, found by search rather than guessed at. Matching that par is the whole game, and the decision that mattered was usually taken several segments earlier.

How to play

1. Press Upshift, Hold or Brake. Each button shifts your gear by at most one step, then moves the car exactly that many segments forward.
2. Read the limit on every corner segment. Your gear must not exceed the limit of any segment you cross, not only the one you land on.
3. Use the three coloured dots: cyan shows where braking lands you, amber holding, green upshifting. A red dot means that move ends in a spin.
4. Finish inside your move budget. Matching par with no spin gives a perfect stage and 300 bonus points; run out of moves and the session ends.

Strategies that work

• Do the braking sum before you commit. Gear 5 down to gear 1 takes four moves and carries you 4+3+2+1 = 10 segments while you do it, so a limit-1 corner must be spotted ten segments out. Gear 5 to gear 2 is three moves and nine segments.
• Treat a spin as three lost moves, not one. The move counts, the penalty adds two, and you restart in gear 1, which needs four more moves and fourteen segments to rebuild to gear 5. The last daily stage gives only par plus three, so one spin there ends the run.
• The first corner never appears before segment six, so the opening two upshifts are free: gear 2 puts you on segment 2, gear 3 on segment 5. The third upshift crosses segments 6 to 9 in gear 4, which is exactly where that first corner lives.
• A boost pad never sits directly before a corner, but its free gear lands the moment you do, and can hand you a gear you did not want. A pad two segments before a limit-2 corner leaves you in gear 3 with one move to shed it.
• Never brake near the flag. The two segments before the chequered tile are always straights, and overshooting the line costs nothing, so carry gear 5 through the closing straight and bank the moves you saved. Crossing at the top of the box also collects the Redline award.

A little history

Redline Apex is original, written for puzzle-me.com, but its rule belongs to an older family. Racetrack, the pencil-and-paper game played on graph paper, gives each car a velocity that may change by at most one unit per turn, which turns driving into planning rather than steering. Redline Apex folds that idea onto a single line: one axis, one number, five gears. The addition is the corner limit, which makes each circuit a constrained shortest-path problem. The par on every track comes from a breadth-first search over segment-and-gear pairs, so it is a genuine minimum, not an estimate.

Frequently asked questions