You can now test any of Steam's games for 10 days.
If you like the game after 10 days, you can buy the game for half off it's normal price.
Steam's website for this is:
"Finally, a 10 day trial of all Steam's games for all CURRENT
users! This means, if you have purchased at least one game, you
can test the rest for 10 days! If you like them after that, you may buy them
for half off!"
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