While you collect coins as Mario on your iPhone, Nintendo is collecting fat stacks on cash.

Super Mario Run has generated approximately $5 million in in revenues after five million downloads in its first 24 hours, according to intelligence firm Sensor Tower. That’s a far bigger download number than competing data firm Apptopia reported earlier today, but it’s in line with data from app-market-tracking company App Annie, which estimates 4.7 million downloads in the United States in the first day. All of those numbers clearly indicate that Nintendo is riding a massive wave of excitement for its first Mario game in the $36.6 billion mobile gaming market. Super Mario Run is the most-downloaded game in 80 countries and the top-grossing app in 30 of those.

“It is easily the best first day for an app launch, game or otherwise,” Sensor Tower head of mobile insights Randy Nelson wrote in a message to GamesBeat.

But this early success isn’t a guarantee of future revenues. It’s possible that this initial spike in spending for Super Mario Run could quickly subside. The game is free to download, and then it has only one $10 purchase that unlocks all of its content. Nintendo has not included any way to continue charging players for more items or levels. So that $5 million won’t necessarily grow in a compound way going forward, which is different from the ongoing spending that something like Pokémon Go continues to see.

“Based on the early numbers we see coming in and the response from consumers, we expect Super Mario Run to initially earn on the lower end of our forecast, around $12 million to $15 million in its first month,” SuperData Research analyst and chief executive Joost van Dreunen explained in a note to GamesBeat. “Requiring players to always be online is prohibitive, and the game is still a bit too heavy-handed for quick play on a phone.”

At the same time, people are enjoying the game. The average player has spent 15.5 minutes playing in the first 24 hours across four sessions, according to Sensor Tower. Those numbers should start coming down soon as players either reach the end of the content or decide not to spend $10. To keep the game performing well, analysts already expect Nintendo to discount the price.

“We anticipate Nintendo to announce a discount after the holidays to keep momentum,” said van Dreunen.

That would represent a break from tradition for Nintendo’s console pricing. The publisher is notorious for taking years to drop the prices of its first-party games on 3DS, Wii U, and other systems.