All key bindings can be changed by selecting Configure Key Bindings....
Default key bindings are:
Up: R
Down: F
Right: G
Left: D
Accelerate: A
Up: Cursor Up
Down: Cursor Down
Right: Cursor Right
Left: Cursor Left
Accelerate: +
In addition use P to pause a game, Strg-N to start a new game and Strg-Q to exit KTron.