Thank you for your comment.
I am glad that you like the game. It suffered from the lack of time I had for it, what is the reason for the lack of a proper tutorial. But I will work on this project at least to the state the game was planned to have for the jams release.
This includes a short campaign mode, more weapons, a few bosses for both modes and ... well... everything the game still lacks, like proper sprites and leaderboards for the arcade mode.
Have a nice day!