Right, that seems more like an (extreme) exception than the rule. I think the more interesting thing with this jump is that it seems to have a consistency in its performance (but then its only about half of the data post inflection, so it may just slip back down after enough time) rather than sharp spikes. Step functions rather than sinusoidal movement.
Does Quiz RPG stay in the top 5 for long or is it more (not smooth) gaussian in its performance?
Somewhat. Here's a 1 year chart:
However, with Level-5, I think you're right in that something is a bit different. One of the things that really sticks out is that it's not only stayed in the top grossing parts of the chart, but the top downloads for an unusually long period of time.
Downloads of big games are often like core games at retail in that they have a huge download spike up front, then drop off really quickly, until the publisher does another big ad round that spikes it up for a bit. Yokai Watch performs more like... Yokai Watch in that it sticks around for quite a long time.
Here's the download chart on iOS as an example:
It's possible it's going to keep climbing higher on the back of getting a very significant amount of downloads, which can help stability and also create some very impressive spikes even for games not draining it all out of power users.
One of the reasons that Quiz RPG has its super unusual behavior is it has over 30 million downloads in Japan, but it's been out for so long that basically their entire audience knows it only makes sense to spend money during events, creating these astronomical swings.
There isn't really a consistent monetization incentive to spend money at other times either like some other games manage, but you know, why risk upsetting the golden goose when it's been around for so long? Colopl's other flagship game (White Cat) is much more consistent though.
Edit:
The game recently hit 3 million downloads:
https://twitter.com/yokai_punipuni/status/671279231662481409?ref_src=twsrc^tfw