This is a great game, but...this game was designed for a 5 MHz, 8088 CPU (from 1979) expecting a system with half a megabyte of ram. (ie. 0.000512 gigabyte.)
The entire game is less than 4 megabytes; that's smaller than a typical mp3.
This game is about as bare-metal simple as can be. It has no digital sound effects; the sounds were generated on the fly using the music card, or using beeps on the PC speaker. The game needs to be given A LOT of slack from modern players. ;)
The developers [Westwood Studios] did not even include the ending cinematic with the DOS version...which GOG most certainly should have rectified for a paid retail product; this could have been done with a batch script that plays a Bink file after the game ends.
When you complete the game, return here, and visit this Youtube Link to see the ending cinematic that should have shipped with the game. https://youtu.be/lFGqrR7Zcl0?t=64