Both options are set in New game before a game, or in the settings.
Blitz
Blitz mode gives each turn 10 seconds. A warning shows when 5 seconds are left. If time runs out, a move is played for you, next to the stones, and announced. Blitz is for local play and games against the AI; it pauses when you leave the app.
Multi-line mode
Lines to win can be 1, 3, 5 or 10. With 1, the first line of five ends the game. With more, lines add up: the first to complete the number wins. If the board fills up first, the player with the most lines wins.
A run of six or seven counts as one line. The threat markers, the hint and the AI all count lines the same way.
Online too
Multi-line mode also works online: choose the lines to win in the lobby. Blitz does not.