GL -> GLES is far from trivial. While code that has 'if( getConfig()->useOpenGL )' parts might support pure SDL (as is the case here), rewriting the GL parts is a huge task. You are welcome to try (not only here, there are tons of apps that could use GLES rewrite, would be very thankful). Aapo is awesome by noticing possibility to compile something which has GL stated as requirement and being able to bring it to GLES device such as N900.