Compos are typically held at demoparties.
The usual format is to show the competing entries sequentially with a video projector, after which the winners are chosen by public vote. In addition to party-based contests, there have also been online compos on websites and bulletin board systems.
Over the years, desktop computer hardware capabilities have improved by orders of magnitude, and so for most programmers, tight hardware restrictions are no longer a common issue.
Nevertheless, demosceners continue to study and experiment with creating impressive effects on limited hardware.
Since handheld consoles and cellular phones have comparable processing power or capabilities to the desktop platforms of old (such as low resolution screens which require pixel art, or very limited storage and memory for music replay), many demosceners have been able to apply their niche skills to develop games for these platforms, and earn a living doing so