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Thanks for that reply SeaGTGruff. I had actually tried enabling VDELP0; this does solve the problem as long as the ships are in the same scanline pair or "row" (one actual scanline apart), as they are when the demo starts. As soon as one ship moves and they are separated by more than one scanline, and player 0 ship (GRP0) disappears with the code I posted. Thanks Darrell, I'll be checking on your posts. Seeing a working example may help clear up the things I don't understand, and I'm not really in a rush.

Needing some help with lining up players vertically in a 2 line display kernel, so I joined the forum. Thanks to readers/responders in advance. I have only basic knowledge so far. I have been using the Stella manual and some other internet posts as references. I picked Atari's "Space Race" as a starting point for a simple, 2 player, time based VCS game. If it gets finished, it might be used for a future local gaming event. The original arcade version is simulated in the Dice emulator: http://sourceforge.net/projects/dice/ This demo is rough and obviously missing most things. 20 lines at the top are reserved for a score display that will be the same style as combat or air sea battle; I don't know how to do this yet so I left it out. It may be relocated to the bottom of the screen to be more like the original. How I'm going to make the asteroids is currently undetermined also. I'm thinking about playfield graphics, 20 rows; with alternating rows going 10 left and 10 right. I don't have a handle on working with pf graphics yet either, so I'll probably demo something separately and see what I can do. Joystick is read for moves to p0 only at the moment, p1 is locked. Horizontal positioning is not being done yet. Question1: I think this is what the Stella manual describes as the "two line kernel". As you can see by the starting positions of the sprites, one ship is one scan line higher. The manual mentions delaying sprites by one line, but I haven't been able to figure this part out based on their description. Given this example code, can someone provide easy to understand hints on how to implement this? I don't know about 1 scanline movement; this game is probably ok with the doubled resolution - but I'd like the opinion of those who have already solved this problem, maybe it looks smoother or has some other benefit. Questions 2: I should only need to position the sprites horizontally once. I've seen some other examples on this (divide by 15 w/ RESP0?) I will try later, but could I put this in my setup code (outside the display kernel)? Any suggestions for optimization or removal of redundancies is appreciated. Keep in mind I'm a beginner with VCS and 6502 code, so I won't have a handle on advanced concepts. I'm pretty sure this game can be done without many tricks; it seems like just a timer, scoring and collision detection once the graphics problems are out of the way. Fair warning - I don't understand the cycle counting yet (and where I should be counting) but I'm working on it. What you see here is trial and error, and even the basic structure is mostly guesswork and learned/copied from example. Thanks, Lee spr001.asm spr001.bin