On the other hand the 1024 x 1024 of the standard display was rather a technical resolution, the visual resolution would have been – according to DEC – about the half (since the bleeding phosphor of the activated blips on the screen would overlap and merge). A closeup of the Type 30 CRT displaying an early version of Spacewar! can be seen here: http://www.masswerk.at/spacewar/decus1962/spacewar-decus1962...
On the storage capacity: Please mind that these weren't bitmap driven displays, all the images had to be composed and refreshed algorithmically. On the up-side, this meant that even a small program could display effective graphics, like Snowflake (see: http://www.youtube.com/watch?v=Y1ioLo2I_5Y) which would only use about 190 instructions or memory locations. Also, consider that these were 18-bit words holding op-codes (6-bit) and addresses (12-bit) in the same instruction word. This was quite more densely packed, like say, in a 8-bit microprocessor computer. For example, I would doubt that (the original) Spacewar! could have been ported to a C64, both for speed and storage, left aside the graphics. (But I could be proven wrong here ... :-))
