Namasu changed to beta 5.

<Change log>
- Add tutorial
- Rebuild stage
- Change from Exe version to Browser version

Reduced the capacity when I rebuilt the stage. Fixed it as a browser version. I checked with Win10, Chrome and Edge.

Namasu :https://nutsmark.itch.io/namasu

In the future, I wanted to make rivers and waterfalls, so this time I made the sea with the test.