Stephen Lawrence Clark
A game with a straightforward premise, offering a reasonably obvious goal, but takes place in an environment which does not have you in mind.
I’d suggest trying it, but “spoilers” are further below!
Download here:
CAPTURE THE FLAG, FOR ONE (Windows)
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Additional thoughts:
As the player carries out the suggested task, the glacier below will shift and melt on its own. Though almost impossible to see, each time the flag is returned a tiny tiny portion of ice will disappear, which slightly speeds up the process of collapse. Intended to be played over a much much longer span of time, the version here probably takes about 5 or 6 minutes.