>>1
One article says CS 1.6 needs 512 kB/s bandwidth to run smoothly.[1] I don't know if this figure is correct, but it's a moot point in the end.
As >>4 said, latency is horrific. From the I2P Performance page:[2]
As the RTT (RoundTripTime) adds up from the latency of each individual I2P node and each connection on this roundtrip, it takes usually 1-3 seconds until a ack package comes back to the client.
Also, you'd probably have disconnects due to tunnel rebuilds:
Used tunnels are discarded every 10 minutes and new ones are built up. This change of tunnels (and sometimes clients that shutdown hard due to usage of "shut down at once" or situations where there is power loss) does sometimes break tunnels and connections, as seen on the IRC2P Network in loss of connection (ping timeout) or on when using eepget.
[1]: https://gamingbeastblog.wordpress.com/2016/12/19/counter-strike-1-6-internet-server/
[2]: https://geti2p.net/en/about/performance