Stack blocks. Manage the tilt.
Tip past 45° and it's over.
A race against the clock, hit the line target as fast as you can without ever letting the ship tip.
A timed take on the cargo-balance game: every dropping container both fills the hold and shifts the ship's weight. Clear the required number of lines as quickly as possible, but a careless heavy side will heel the deck over and end your run before the finish.
The same original cargo-stability idea as the rest of the Keel family, cut down to a time trial: reach the line target as fast as possible without ever tipping.
Speed and balance are natural enemies here. Every fast decision is a placement made without full consideration of trim, and the ship keeps the consequences.
That is the sprint's whole argument. Given unlimited time the problem is nearly always solvable; the mode exists to find out which parts of your judgement survive having no time to check them.
Keel: Sprint is an original arcade puzzle combining falling-block line-clearing with a balance mechanic and a race format, a free, fast browser game in the Keel series.