gemini://gem.sdf.org gives me less errors than gemini://sdf.org, so go there:

gemini://gem.sdf.org/iiogama/

Proxied content from gemini://sdf.org/iiogama/ (external content)

Gemini request details:

Original URL
gemini://sdf.org/iiogama/
Status code
Success
Meta
text/gemini
Proxied by
kineto

Be advised that no attempt was made to verify the remote SSL certificate.