The producer of video game franchise Angry Birds went public in September, attracting investors who were keen to to grab a piece its stock and prompting one of Finland’s hottest IPOs since Nokia’s a decade ago. Though the IPO only gave Rovio half the market value the company had hoped for (€900 million ($1.1 billion) instead of its anticipated $2 billion), stock bounced back when a bank backing the IPO started purchasing shares to “stabilize” the price, according to Bloomberg.

By October the bank’s efforts had ended, and by November 23 Rovio revealed that its marketing costs–which had included a full promotional campaign featuring neon billboards, full-page newspaper spreads, and bus ads with company’s trademark scowling birds–had soared. In all, the company said in an earnings release last week, investment in ‘user acquisition’ had risen to 22 million euros in the quarter – nearly three-quarters of the 30 million it raised through the IPO.

As a result, the shares dropped 22%.

“I’m disappointed in what they had led the market to believe,” said Tomi Lahti, a Helsinki investor who bought stock in the offering, to Bloomberg.

Rovio said it expected its increased investments to pay off within eight to 10 months.

The problem appears to be that Rovio is overly dependent on Angry Birds –a game where users catapult sullen faced cardinals, canaries, and eagles at a variety of structures and formations to knock them down. Rovio launched the original in 2009, and has since brought at least 25 variations of the game, from Star Wars-, Transformers-, and Rio-themed versions. Then in 2016 it co-produced The Angry Birds Movie for $100 million, bringing in nearly $350 million in ticket sales.

But when it comes to the mobile gaming front, the company has been less successful, as less than 5% of users tend to play a game for more than a month with the frequency of updated games released.