Retromino may refer to Retromino(exe) or Retromino(js) The two are different games made by the same person and they both share the same name and graphics which can be a little confusing.

Retromino(exe)

Retromino(exe) is a fan game written in C++ by Blitz. It’s mechanics are similar to NES Tetris with the main differences being that pressing left or right during line clear or entry delay results in full DAS charge and holding a rotation button during entry delay results in the piece rotating immediately after it spawns.

Game modes

Easy Mode: A mode that plays similar to NES Tetris A-TYPE

Death Mode: A faster paced game mode that starts at 1/2G, 8 frames of entry delay and 16 frames of line clear delay. Entry delay and line clear delay will decrease as you clear lines. Smaller line clears will cause the speed of the game to increase quicker than larger line clears. The objective of this mode is to clear as many lines as possible.

Retromino(js)

Retromino(js) is a javascript based browser fan game. Unlike Retromino.exe, it does not attempt to replicate NES Tetris. Instead, it delivers it’s own unique gameplay inspired by classic Tetris. The game has one next piece and uses the memoryless randomizer. The line clear delay is 20 frames and the entry delay is 18 frames. The gravity table is as follows

Level Frames per gridcell

   0      120
   1      100
   2      80
   3      60
   4      40
   5      35
   6      30
   7      25
   8      22
   9      20
   10     10
   11     9
   12     8
   13     7
   14     6
   15     5
   16     4
   17     3.5
   18     3
   19     2.5
   20     2.4
   21     2.3
   22     2.2
   23     2.1
   24     2
   25     2
   26     2
   27     2
   28     2
   29     2
   30     1.9
   31     1.8
   32	   1.7
   33     1.6
   34     1

Game modes:

Upstack mode: A Marathon style game mode. This mode uses the original Nintendo scoring system http://harddrop.com/wiki/Scoring#Original_Nintendo_scoring_system The level is calculated as follows: If level is less than 18, level is equal to (lines cleared/10) + total number of Tetrises. If level is not less than 18 and lines cleared is more than 179, level is equal to (lines cleared/10).
Entry delay decreases to 10 frames on level 24.
Level 18 skip:
It is possible to advance from level 17 to level 19 by scoring a Tetris on level 17 when the last digit of your line clear is 6, 7, 8 or 9. The player can take advantage of this to potentially score more points but it is a risky strategy as gravity is higher on level 19.

Downstack mode: A game mode with focus on downstacking. The game starts with 5 garbage lines and adds one garbage line when the following conditions are met:
The garbage height is less than 5 and the level is less than 17
The garbage height is less than 3 and the level is less than 21
The garbage height is less than 2.
The level is (line clears + garbage line clears) / 10 and the scoring system is (800 * garbage line clear) * (level + 1).

Mix mode: A game mode with focus on upstacking and downstacking. It has the same level and scoring system as Upstack mode but every time you clear a Tetris you receive one garbage line. Entry delay decreases from 18 to 14 frames on level 26.

Fashion Mode: This mode can be found in the settings menu. The statistics panel have been replaced with more than a dozen buttons, which allow you to customize the colors and appearance of the game. The objective of this game mode is to find your inner fashionista and play around with the colors until you are happy. Any changes made in this mode takes effect in all other game modes.

Misc

Automatic soft drop: This game introduces a new feature called automatic soft drop. When this is active, the game plays as if you are always pressing soft drop when you are not pressing left or right. This can be toggled on/off at any moment by pressing the key associated with it.

External links

Download Retromino(exe) https://tetrisconcept.net/threads/retromino.2999/

Play Retromino(js) in the browser https://zyphdoz.github.io/