Intentional. You start the game with 5 Peeks (You have the counter on the right side of the UI) and if you run out of them you cannot Peek anymore. There are actually cards which give you extra Peeks, but I had to scrap them, along with more encounters and upgrades, because I ran out of time (I could only spare 6 out of 10 days of the jam, because of work). Thank you for kind words, this theme really made me push my skills!
However I think I could grant 10 Peeks instead of 5 then when I scrapped the upgrades. That's an overlook on my part, sorry about that! Nevertheless, the game's still beatable fortunately. I managed to win it within 5 runs with 4 dollars still in my pocket. Aggree the game should notify about the lack of Peeks, besides an emptied bar tho, will do that after the jam (along with an improved, longer version with ugprades!)