My game crashes/freezes in certain(?) environment


My game is on Steam and a guy recently reviewed my game on youtube.

But sadly the game crashed several times. :smiling_face_with_tear:

(Crash happens at 2:55)

It worked and still works perfectly on my desktop (Windows10).

I tried it on my old laptop(Windows8.1) and the game crashes(freezes) in a similar way!!
(Some events don’t go through. When X key is pressed those objects should be deleted but it freezes. Keyboard output is slow. When keys are pressed the output lags.)

I cannot figure out what is the cause.

Only differences is that my laptop is old and it is Windows 8.1.
(Intel i3-4020Y CPU, 4GB RAM, 64BIT, Windows 8.1)

What should I do when the game works fine on some computer but not on some others??