Cosmo Dreamer TRIAL Expert 1cc (Shot Config BBAC)
3TRIAL is the all-stage mode of the game. You have to beat each stage individually first to unlock Trial for a given difficulty. Expert is the second highest difficulty, I was able to do it comfortably (the later stages took 1-2 tries). Nightmare is more difficult and will perhaps come later.
The system of this game is pretty simple, you have lives and bombs. Bombs are refilled by grazing or otherwise collecting the blue bubble items. When you have more than one bomb in stock, you get a shield, but if you break the shield you lose all your bombs. So it's always advantageous to bomb and not break shield. There are deathbombs like Touhou, and the timing is generous.
Buy the game here (it's on sale right now): https://store.steampowered.com/app/1424630/CosmoDreamer/