From DoomWiki.org

C2Doom is a Doom port for Symbian OS, made by Markus Mertama. It is based on CDoom for Nokia 9210, which was developed by Markus also (Hannu Viitala was developing it with Markus). C2Doom uses Simple DirectMedia Layer in its drawing functions. It supports Symbian OS Series 80 v2.0, Series 90, Series 60 v1.2 and up. The phone models Nokia 7650, 3650 and 9210 are not supported.

Source code genealogy
Based on
CDoom (mobile)
C2Doom None