I think the directory is nested too deep, top entry in the ZIP file should be just "Rail Gunner.pdx" as opposed to "Rail Gunner/Rail Gunner.pdx". Also, "pdxversion" and "buildtime" lines are duplicated in the pdxinfo file, and bundleID is missing.
Viewing post in Rail Gunner jam comments
Agreed, I've just discovered these and fixed these on my own. My pdxinfo looks like this now, and the game sideloads and is working with it:
name=Rail Gunner
author=4 gatti
version= 1.0.0
imagePath=images/meta_images
contentWarning=This game was made during PlayJam 9
pdxversion=30003
buildtime=824589740
buildNumber=1
bundleID=com.4gatti.RailGunner
I like, how they integrated different playdate inputs like shaking, cranking and dpad.
For the worse things, aside of the easily fixable package errors. - It would really help to make the aiming reticle more visible, especially for the revolver. I die after shaking, because I waste my time for searching the reticle on the screen.
Also the game is really punishing right now, at least for me. Some difficulty options or gradually scaling the difficulty - enemy speed over time would be nice.
In general, it's a promising game, which I would like to see in the catalog in the future, but it needs some polish.