Advanced 3D graphics! Dual-stick controls! A deep, engaging story! Bitcoin Billionaire from Noodlecake Studios has none of those. Yet, it's still somehow addictive and... I don't know if I'd say fun, but something resembling a type of fun.
Here's how you play Bitcoin Billionaire—tap. A lot. Each tap earns you (not real) Bitcoins based on how powerful your mining rig is. You can also tap with more than one finger, or even both hands if you're really into it. Your coins can be spent on miner upgrades and better stuff for your pad. There are also Amazon delivery drones dropping off random bonus packages and a variety of other events to keep it interesting. If you've ever played Cookie Clicker, this is similar.
This is a free-to-play game, but I have to hand it to Noodlecake for not being jerks about it. There are in-app purchases for special premium currency (hyperbits), but you earn a lot of them from playing, and there's very little push to spend money. Additionally, it's clever how Bitcoin Billionaire will offer you the chance to get bonuses by enabling banner ads for a few seconds or watching a short video. It's not really annoying at all because the ads feel like part of the game.