And I’d assume you contact him through the DevForum DM’s as he has not provided any other way to contact him.
(Slinky really should have a contact me section though).
Why would someone making an entire zombie game sell it to you and let you reap the profit from players rather than just doing that themselves? If you wish to make a game with someone else, it’s a more common and sensible approach to split the revenue with a partner, rather than hoping someone would sell all their work to you for a lump sum, which is potentially a mere fraction of the revenue.
If you include every system to make up a game, then it doesn’t functionally differ from a game. I’ve yet to see a ‘system’ that, by itself, could be considered playable.
Bugs are unpredictable therefore unless the programmer hired is willing to look through their source and eliminate any bug than this aspect of the request isn’t possible. Contrary to popular belief a large proportion of programmers will not do extra work if it isn’t specified in the assignment’s description meaning if for f.e “Updating the source on a weekly, monthly basis if necessary” hadn’t been mutually agreed upon than it won’t be obligated of the programmer.
I wouldn’t recommend having another programmer take over the project neither without getting familiar with their skillset.