Ask the programmer. They will be able to tell you for sure, everyone here can only speculate. Don't feel like you're bothering them, it's a completely reasonable thing to ask.
Max size, file type, compression can be hugely variable.
WAV is a lossless raw format, so the short answer to your question is no.
The only way to reduce the filesize is to :
use a different export format, or
shorten the length of the project.
There are various lossless compression tools available to you such as WAVPack, FLAC.
The lossy compression tools that could be considered are aac or mp3.
StuffIt's SITX has algorithms for compressing uncompressed audio formats built into their format, and I've known a lot of people who use it when Digidelivery/Aspera isn't an option and we have to resort to FTP et al.
Luckily they are now Win and Mac (used to be Mac only), so it's become a universal format, although not quite as deeply-compatible as say ZIP, ...
Although FLAC encoding is always lossless, it still offers different compression levels to choose a tradeoff between size and decoding speed.
So, the unexpected difference in size that you noticed may come from different compression levels between the files.
Try to re-encode the cropped file with maximum compression level (8) and compare sizes again.
Hi there. I use Logic 9 and save PCM Wav at 22050hz and play back is fine. I'm not sure why you're getting problems with the speed?
20mb goes a long way if you use it efficiently. Keep files sizes low by saving as mono, keep SFX to <0.5sec. Loop SFX for longer instances. Use pitch changes to create variations.
It really really varies. And your programmer is going to be the one to answer it. Every game on a different platform is going to be different.
It used to be audio would get 10% of resources (RAM, disk space, CPU...) but even that changes and has never been constant.
And yes, MP3 does not like to loop. It pads files to fit the block size it needs which is ...