X-Com: The Bureau Declassified. Your “teammates” are fundamentally suicidal, making keeping them alive almost impossible. But the setting, story and challenge made up for it. It was inventive.

The Technomancer: Mid-budget game by Spiders. Was short and straightforward, which most people disliked, but I thought it was a blast. The story still sticks in my head screaming for me to write a novel based on it.