That's not how you make a boss. This is how you make a boss. Notes: -multiple stages -multiple attacks -weak points -menacing appearance -proper boss music -enivronmental attacks -intro, boss health bar -backstory, relevance What's currently wrong with the bosses: -the lack of above things -exploiting safe spots is the one and only effective tactic (sandboxing them, building arenas to counter them) -melee against them is awful because their hitboxes don't match the sprite, and they do massive contact damage -their AI is pretty bad (dragon uses bird AI which includes severe amnesia and ADD, robot is just bad at combat in general, ufo is not so bad) If you want more examples of great bosses, take a look in the SNES era.
They need to prevent boxing and improve their AI. The dragon will always over shoot you if you stand still...
The second two bosses are obviously unfinished. Also you can't really compare a final boss to three early ones, don't forget that the game you linked to has extremely simple bosses aside from that guy too.
The first boss has a lot less problems, but it still lacks good bossy elements. That fight is quite spammy too, and melee is pretty useless.
