I actually like the bag one, knowing where in a bag you are gives an edge, and thus it adds an extra dimension to the game I feel.
>> The clumsy 7-bag is unnatural feeling, but allows for many building strategies to be consistently viable.
And consistency is one very important component of multiplayer games.
However for solo play where you end up playing at 20G, the seam problem (repeat of SZSZ) can wreck your game if it happens when you have an unfavorable shape of the stack and/or if you get caught up by the lock delay.
for the non-initiated: the piece spawns directly on the stack, on you have only a short time to react and place you piece
It is only possible to play 20G if you have what is called TLS (Temporary Landing System) and IRS (Initial Rotating System) in TGM games. This means that even before your piece spawns and falls, you can rotate it by one rotation either clockwise or anticlockwise and when the piece drops, it doesn't lock into its' place immediately, you can move it for a short while.
Also, if the piece drops vertically, the locking time resets which means that you should build a pyramid shaped stack so that you can slide your pieces down on either side and rotate it where you want it before it locks.
No need for unnecessary complications - the pice becomes less numerous and less likely to come when there was a flood, and more common and more likely to come when there was a drought. You can even add a set aften less than seven pieces, to increase randomness (and thus difficulty) over time.
Playing infinitely in Tetris means repeating a pattern over and over again. I would suspect that transforming Tetris so that it is universally infinitely playable (probably by somehow erasing the fact that an infinite SZSZ is a death sequence) would lead to a game where the optimal play is also to repeat a pattern over and over game.
It would be indeed a game of skill but would rob the player out of all creativity and agency. Not a very fun game at the end.
But I think that proving that such game is infinitely playable is a hard (np hard ?) problem.
Not necessarily - you could define an infinitely long non-repeating sequence (although it will have arbitrarily long repeating sequences inside it) which would still not contain any certain-death sequences.