Hello !
Thank you for playing the game ! That's great to see feedbacks !
I have uploaded a new version of the game and corrected lots of bugs you are talking about.
Controls are "ZQSD" and arrow keys. I will make later a menu to change it to "QASD" because arrow keys are good enough for now.
The level 3 was made for the player to discover bombs but maybe it was not intuitive, so I added a tutorial on level 1 for movement and level 3 for bombs as you suggest.
Explosive bullets cost 0 coins and now 99999 because I didn't implemant them yet so they do nothing for now :)
I corrected the bug when you end the level with one enemy alive, It was due to a bug with double bullet, please tell me you had double bullet on level 10-11 when this happens ?
Level 12, there was an enemy behind the three but you couldn't see him except if he shots you so now he is visible, it's easier for the player to understand.
For the level scroll, I don't know how to correct it but if the player scrolls too much, maybe he wanted that to happen. Moreover if you go to the main menu and come back, the scroll rect gets reset so it's ok.
Thank you for your positive feedback and your help, that really helps me and give me the desire to continue this game. Don't hesitate to let me know if you see any other bugs !