I walked leisurely through the first level, and my interactions with the second brought on a desire for more immersive flair in lieu of difficulty before I got slightly lost because the keypad and door are separate objects. The third level tested my patience with several attempts burned on failing to escape after self destructing; one especially tragic misfortune was teleporting and getting trapped underneath the stairs, which didn't block the light's damage; I suppose that's ultimately preferable from actually getting stuck and needing to restart the entire game.
The game is a thoroughly tread path of stealthy Nerve mazers versus spotlights, offering its unique motif of light exposure acting directly as a health bar. In the second level I encountered several small lights which I felt should have an effect on me, perhaps only part of the damage's visual and somatic effects with none of the damage, to create consistency for the character and to initiate the player on being in light for short periods in order to complete certain tasks or escape enemies. The third level had a satisfying challenge, although the late inclusion of the shield guards felt too slight; since they already perform bullheaded charge attacks I feel as though their speed and path could have been extended to quickly race through the maze of matrix pillars (and perhaps put a checkpoint after triggering the escape.)
For nearly every mainline Metal Gear Solid game there had been a "torture minigame" in which the player needed to mash buttons for constitution in order to survive the ordeal. Although these sequences do have a fail state, their scripted nature is still a simple shorthand for dramatic tension; essentially a well paced and placed quick-time event.