Fastest would be copy paste many things from ehre:

https://github.dev/hajimehoshi/ebiten

Todo

Bug Fixing / Missing stuff

• Sounds!

Upcoming Features

• Make some monsters move laterally
• Try more columns maps

Possible Future Features

• Random Map Generator
• Custom Map creators
• Canon bonuses (multipliers?)
• Different kinds of canons
• Types of monsters/canons

Maybe rely on a server, if it's worth to spend time on that