tetris is RNG but still predictable

Tetris is a bite-sized single-player game, though. If that randomness had some serious impact beyond 5-10 minutes of play to the average player, it would likely call for more controls, and if there were somehow this multi-million-player competitive PvP mode around it, the randomness would certainly be criticized. Crits are already controlled via their pseudo-randomness, which severely limits edge cases where either side gets spectacularly lucky, and even then it still does not feel fair. Because of this, I think it would be worth looking into ways of adding variety to the damage output of marksmen that relies on actual gameplay and interaction with other players, rather than a continuous diceroll.

Less than 50% chance will most likely not crit Greater than 50% chance will most likely crit

It's predictable but still toxic.