What is the Bullet Hell Monday game, how does it work?

According to the introduction of MASAYUKI ITO, Bullet Hell Monday is a Arcade game on the Android platform. There is currently a 2.2.0 version released on Sep 04, 2019, you can see the details below.

Why don't we play a bullet hell shooter?
For you who think shmups are hard.

A bullet hell shooter
- Enjoy an authentic bullet hell shmup on your smartphone!
- Recommended Chapter mode for danmaku beginners.
- Recommended Challenge mode for danmaku expert.
- Huge content: over 50 stages and 3 modes.

Upgrade your ship
- Use the points you earn after playing a stage to level up your ship!
- Take your new and upgraded ship to the challenge mode! Aim for a high score!

Chapters
- Best suited to the introduction of bullet hell!
- Starts from an easy stage, so you can gradually improve your skill!
- Clear the missions set for you in each chapter!
- Clearing missions opens up new stages!

Challenges
- The challenge mode is for when you really want to test your mettle!
- Upgrade your ship and take on this mode!
- Select from EASY, NORMAL, HARD, and HEAVEN difficulties!

Endless
- The endless mode that lasts forever.
- How long can you survive in the increasing difficulty?

Aim for the top slot in the rankings!
- Challenge mode has online rankings!
- Rankings are sorted by stage and difficulty!


*** Attention of purchased item refund ***
Please be careful. If you refund the full upgrade item, the relevant level up item will return to the initial level.

*** FAQ ***
- Can I transfer my game data to my new device?
You can use the in-game cloud saving function.
It can be accessed from the i icon at the bottom of the main menu screen.

- Can I restore my purchases to my new device?
Yes.
You can restore your purchases with the same Google Account.
Please tap the "RESTORE" button which is displayed instead of price on the purchase screen.

- Can I synchronize my game data with other devices?
You can use the in-game cloud saving function.
I does not synchronize automatically, so please synchronize manually.

- Purchased item has gone or not reflected
Please try the following URL steps. If your purchase info recovers normally, you can restore by tapping the "RESTORE" button which is displayed instead of price in the game screen.
https://support.google.com/googleplay/answer/7513003

Bug fixes.