02.wav - sounds better at half speed. I wonder if somebody tried to imitate the (incorrect) original sound (which should be played at half speed, ie, 11KHz, instead of 22KHz).
10.wav - sounds good
10 remade.wav - perhaps a bit too much extra echo?
12.wav - pretty good
21 - beep.wav - that's sounds fine
22 - wipchat.wav - sounds good to me
22.wav - closer to the original, sounds a bit "tinny" though, as if it's been taken from 8-bit and converted forcefully into 16-bit
24.wav - nice
29.wav - sounds like a gameshow

37 human moo.wav - well, that's... interesting

37.wav - maybe a bit better
65 - maglev.wav - funky, nice and futuristic
chainsaw.wav - yes, that should work nicely. (24-bit, too!)
electricity.wav - I think this one is a bit too long, I prefer 12.wav personally
Ooooh2.wav - same comments as sickie, needs a few more people, but not too many
Pop.wav - that works alright, indeed
Now, then important thing is - legality. Some of these files were taken from Creative Commons-licenced materials, I gather. Can the people who worked on these please check the original licence, the terms of it (derivatives allowed?), and if redistribution and reediting is allowed, please make a list of the original authors and links to their material? This will be essential if we are to distribute these sounds with OpenTTD.
Legalities aside for the moment, good work, guys!