I fail to see what it is about being Open Source has to do with anything. I think you just want to piss on open source, which is fine, but in this context it means nothing.
This is a free port of a game originally made in 1999. It was built as a clone of that game. Do you expect just because time has passed that the game should be reimagined?
The devs do this in their free time as a hobby. Being open source or not has no bearing on the points you are trying to make. Just because the game is old doesn't mean a dev shouldn't be able to release an update.
As for accepting inferior products, go and check out Greenlight and how well some retro indie games are doing
You have a warped taste for what is adequate. Perhaps you should go play some more CoD:Ghosts.