5th option: Let me try part of the game for $10 and if I like it give me that amount in discount for the whole game.
SO MUCH THIS. I'd absolutely love to try out just 15-60min. of any game out there for like 2-5$, with the option to pay the remaining price to remove the timer.
I buy a lot of games which I'm not sure whether I'll like them or not once they're on sale for 2-8$ instead of full 40-60$, and I always can't fight the feeling the developer is missing out huge money, because if only I got to check out the game earlier I'd buy it for higher price, but now he got like 5 bucks from me and that's it.
Becauae there are so many games that look good/interesting, but the price point is set to high to just blindly give those games a try where it might turn out you'll drop it after mere 15-20min... And vice versa, there are games that maybe don't look that much fun/interesting at the first glance, and the full AA/AAA price is only making things worse, but for just a few dollars you don't have much to lose to just give them a try.
This issue is mainly due to the fact that in modern day demos are sadly extinct, and the only option to try out games for cheap instead of buying them blindly for full price is either sales or Game Pass.
I understand that creating a seperate demo takes time and resources, that's why they're so rare nowadays, but selling a full game with a time limit shouldn't take that much of an effort.