Don’t get me wrong, some of the puzzles suck. The section where you have to eyeball the height of 6 different levitating platforms with buttons that are extremely far away from each other? Even Bungie admitted that puzzle was a mistake.
And the final mission is pretty bad too. You basically have to guess where to go in lava before you run out of health and pray that you don’t get shot at enough times before you make it.
Other than that, the game is good, especially for 1994. Better than Half-Life. At least I felt compelled enough to beat it.