Keno

Ten numbers are drawn from a pool of 40 by shuffling the whole pool with a Fisher-Yates shuffle seeded from crypto and taking the first ten — an unbiased draw without replacement. Pick 1–10 numbers; how many of yours are drawn decides the payout.

The paytable for each pick count is derived, not hand-written: pays rise geometrically from the minimum paying hit count, then the whole row is scaled so the exact hypergeometric expectation lands on 99% — and the published RTP is recomputed from the rounded numbers that actually get paid.

Risk changes the shape of that table and nothing else. Low pays earlier and flatter; high pays nothing until you are nearly perfect and then pays enormously. Every level is rescaled back to the same 99%, so risk buys you variance, never a better or worse deal — and npm run rtp checks all four at all ten pick counts.