while this looks nice, it's actually not possible on real hardware ... O2/VP has a lot of limitations that prevent cool tricks that are possible on other systems:
- processor speed and speed of the raster beam do not correlate in one frame, so it's not possible to do "mid-line-changes" always at the same pixel (something that on the Atari 2600 is frequently done ("Racing the Beam"))
- characters can not overlap (the result is unpredictable - the demo above would result in distorted characters and wouldn't look like in the video)
that being said - if you really dig into the hardware of the O2, there are still things that you can do - and lots of homebrew games show what is possible (e.g. the games of Revival Studios for example make good use of the hardware, as of course Rafael's game do - and just take a look at what Ted did with polyphonic music in Puzzle Piece Panic! - another thing nobody ever thought would be possible ;-) )