I've been thinking about this for a while now and I've got some great ideas! (I hope!) I saw a Tetris-clone called "
Puzzle Master"
that gave me a lot of initial inspiration for a Tetris-like DROD game. It demonstrated that the Tetris playing field can be used for a lot more than just dropping blocks! Some modest screenshots can be seen at:
http://www.videogamereview.com/reviews/Nintendo_Gameboy/Puzzle/moreinfo_699.asp
and a review (if you're interested in the gameplay) at:
http://pocket.ign.com/articles/162/162326p1.html?fromint=1&submit.x=65&submit.y=13
Please take a quick look at the screenshots to get a vision for what could be put in a DRODTris.
Making elements work in a roughly DROD-like fashion might just work, and provide some original and refreshing strategic gameplay in a Tetris-environment rather than just random action.
In short, each "
room"
(one Tetris-like level) could be hand-crafted with certain elements placed to provide a strategic puzzle. Like walls, doors and orbs, tar, and monsters placed in certain ways.
Rather than dropping blocks, how about having Beethro standing in the top row of the room and dropping swords in various random configurations (one, two, or three/four connected together in a certain way). Beethro moves left and right, always positioned above the swords, as you maneuver and rotate the swords in their downward fall to land on something. Only those swords that are actually on something when one of the swords hits has any effect. Each "
move"
(dropping a block of swords), the monsters would try to move one step towards wherever Beethro is standing (according to their movement patterns) when the swords hit. You lose if a monster gets Beethro. You win when the room is clean of monsters (as you'd expect).
Now here are the elaborations to give it some meat! Dropping a sword on an orb would cause it to act. Opening and closing doors at the right times would be key to completing some rooms successfully. (Orbs and yellow doors don't go away when hit, just act as usual.) Tar needs to be hit at certain spots (as usual) to cause it to break as needed. Roach queens and tar mothers spawn only every so many moves (I'm thinking 10-20, but we'll have to get a feel for what works best based on "
room size"
). Serpents are too tough, so they can't just move up (into "
space"
) and eat you. Instead they just move back and forth on top of whatever objects they happen to be lying upon at the time (picture a side-view DROD, and how snakes would move there). Hitting a mimic potion allows placing a mimic anywhere, and it moves left and right as you do (its sword only points left and right). It, of course, stays around until stabbed. Green doors disappear whenever all monsters
above them on the screen are removed. This would allow for multiple green doors opening at different times while playing the room.
You could have an overall DROD-like feel to the game, like a map screen for each "
level"
(set of rooms) where you select which room to play. New "
rooms"
would open up as old ones are cleared and you select which one to play next. (I'd expect most levels to feature only green doors, and maybe only the final one in a level would have a blue door that works basically like a green door.) Anytime you lose a room it gets reset and you go back to the map. It's probably also good to allow exiting play of a room at any time to return to the map.
I think this could be pulled off. I'd be excited to play a game like this (and design rooms)! Let's go for it!
____________________________
Gandalf? Yes... That's what they used to call me.
Gandalf the Grey. That was my name.
I am Gandalf the White.
And I come back to you now at the turn of the tide.
Almost as satisfying as the ka-ching of an old adding machine! 
