Tetris: Shrink Mode

This is Shrink Mode, a romhack of Kirjava's romhack https://www.romhacking.net/hacks/6335/.

Choose between Small, Medium or Big.

Big mode, inspired by Tetris: The Grand Master, doubles the width and height of each block, reducing the playfield to a mere 5x10.

Small mode is like big mode, except the pieces are smaller. The reduced size of the pieces increases the playfield to a massive 20x40.

Medium mode isn't very different from vanilla gameplay (see limitations below) and exists simply to provide a size option between big and small.

Prefer to play all three at once? Try the Shrink mode challenge. Start the game in big mode on level 9. Advance levels every 10 lines and if you can survive 100 lines the board will convert to medium. Survive another 100 lines and the pieces shrink again to small at level 29 where the speed and size stays stable for the rest of the game. How far can you make it?


Other features:

* Seed. Not a playable option but any seed selected will apply to any mode. This is included mainly for any competitions involving big mode where RNG can make the most impact. To quickly clear a seed, press A+B.

* DAS. Defaults to the vanilla gameplay with setting G (16). Reduce this value to increase the speed in which the pieces automatically shift when left or right are held. Like Seed, this is also not a playable mode and instead will apply to any mode.


Known limitations:

* The logic for line clearing had to be rewritten to accommodate different size playfields and does not include the top row bug from the original game.

* Also missing from the original game are ceiling blocks. In this version any block that locks above the visible playfield will disappear into the ether.

Changelog:

v1.1:

* Fixed bug that didn't return to correct menu after end of shrink game

Database match: Tetris (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: 77747840541BFC62A28A5957692A98C550BD6B2B
File CRC32: 6D72C53A
ROM SHA-1: FD9079CB5E8479EB06D93C2AE5175BFCE871746A
ROM CRC32: 1394F57E