We'll have an official Windows client coming out shortly, which won't have these same security concerns.
Why not go the hybrid approach and make it open source so people can understand and audit it. You could still ask for donations or even provide a compiled version for some dollars like http://www.blink.sh/
zx2c4: Would it be possible for you to configure the WireGuard demo server so that it detects if there are interoperability issues with other clients?
Either way. The L2TP/IPSec implementation in Windows 7 I use now is also closed-source proprietary software. So I can't see that TunSafe should be worse since the author is public. I guess TunSafe will not be able to communicate with the wireguard servers if it does not use the correct encryption and protocol scheme?
There's a lot more to writing secure software than merely implementing something that appears to speak the protocol some of the time, or merely implementing a protocol at all. As I said, don't rely on TunSafe.
As above, we'll have snapshots of the cross platform implementations shortly. Until then, I'd recommend just waiting patiently.
"appears to speak the protocol some of the time, or merely implementing a protocol at all"
ludde: Is the wireguard protocol fully implemented or just partially implemented in the version that is on the homepage?
there are currently at least two actively developped open source userspace implementations in different languages. Two examples are Go and Rust: