I was learning MRM's Tetris route and came up with what I think are improvements (but my Tetris play isn't fast/consistent enough to know for sure). They're the same through the first 40 or so tetrominoes but there are some changes near the end.

MRM's route uses 66 tetrominoes and 8 line clear delays. This route gets a Tetris with the last I, getting it down to 65 tetrominoes and 7 line clear delays, and it doesn't substantially change the stack height. The only way this isn't a timesave is if this takes longer to position the pieces.

This route uses the optimal 63 tetrominoes (63 4 is 252, the smallest multiple of 4 >= 25 10) and 7 line clear delays. However, it's a lower stack for much of the later part of the run, so it may not actually be faster. My personal best is faster with this than the previous route, but agan I'm not consistent enough to tell for sure.

I gotta say, to see someone else use MY build is extremely flattering. Smiling from ear to ear.

I optimized the 63-piece route a bit more, to delay line clears and play the stack as high as possible as long as possible. Still started from MRM's but deviates a bit earlier, and man does it include some counterintuitive drops.

It's still possible that 65 pieces could be faster, because it might keep the stack higher longer, but I haven't routed that one.

I have a 4:14 that I haven't submitted.