SO IT'S BEEN A WHILE since I've been very active on AA; but in the last few weeks I have again started some fairly intensive 2600 development.  I'm sorry to say, Nathan, that it isn't RPS - which is still on my slow-moving to-do list - but rather a project that I toyed with years ago: a semi-faithful port of Tank Battalion.

I'll try to find time to put up the in-progress ROM of what I've got so far along with some screenshots, plus other details.  And I am having some difficulty with the graphics and could use some help from those who are more talented.  But I'll save the begging for later.

EDIT: Now I'm at home; here's a screenshot and a binary.

 TankMaze20120123.bin (4K)
downloads: 28

It's pretty ugly at the moment.   The explanation:
I'm trying to use the same technique that batari used in his Rally-X demo - using the missiles as alternate frames for the sprites to have 4 semi-flickered sprites.  The ball (flickered) will be used for the tank bullets.

The current ROM has two different graphics in it - the original graphics I came up with are used for the L/R-facing tanks and the downward-facing tanks.  The upwards-facing tank uses another version.  I'm not really satisfied with either.

The constraints are:
the sprite is 8x12, which isn't set in stone.
The missile can only start or stop drawing on even-numbered scanlines.  I.e., they can only be 2, 4, 6, etc. lines tall and the can only be positioned (vertically) every two lines.  They can be 1, 2, 4, or 8 pixels wide.  The missiles can only be rectangular in shape - they can't have blank lines in the middle or change widths in the middle.

Anyone got anything better, or have any good suggestions?