This game is the definition of fake difficulty, every single battle is poorly designed to a point where if you position yourself correctly you can crouch, mash A and ocasionally jump and beat 80% of the game easily, add this to the unreasonably high amount of HP the 3-4 final battles have and the only way you can screw up and die is out of boredom or the wonky hitboxes/jumps. Im not exagerating in the slighest bit, I´ll explain how easy/flawed the game is battle per battle.
-I´ll forgive you the first 2, because they are meant to be simple.
-Black EVE: Crouch in the middle screen and mash A, jump when needed and you´ll eventually beat it.
-Clankagram: Just move left right jump n´ shot the attacks are easy to telegraph.
-Robocorpse: Move to the left, jump, shoot. The hitbox is wonky and you have to get used to the uncorftable jump.
-D-X: Crouch and you can avoid 2/4 of is attacks, the other 2/4 is jumping. Very Telegraphed. Just adds 2 new attacks to the 1st boss.
-Devalek: This battle is better designed, but it´s still super easy.
-Death/Hell Bender: The only battle you designed decently, no complains, have to keep yourself moving, be aware were to shot, not going "jump happy", pretty good.
-RoboJesus: Crouch in the 1/4 left part of the screen, and mash A. If you do that, there is literally only 1 attack that you have to take care of: when the sign appears over your head (move foward, after that, back to the previous position).
-3rr0r: You ran out of ideas right? 1st, 2nd and D-X boss in a row. Stupidly easy, just time consuming. Which is plain bad game desing. There is no need of repeating those bosses, at all, unless your objective is to bore the player.
-Hellevator: I know it´s supposed to be a joke boss, but still: Crouch in the middle screen, spam shot, jump when low attack.
The character design it´s simple, but lacked effort, no shading or anything worth noting. The music choice doesn´t fit with the atmosphere you try to give the game. The controls are very, very wonky, poor mobility and the bullets are kinda slow. Lack of decent animation in general.
Don´t get me wrong, the CONCEPT of the game has potential, but the execution is poor to say the least. The game feels very cheaply made, and doesn´t reward the player at all.
If you make these games for your own fun, it´s ok, but don´t expect any good reviews from people that analize the content objectively.
Things you could do to improve:
-Work the artstyle, put some effort into it and the game will look much better, this is pretty much a re-skin of your previous games with 0 improvement. May I call you the CoD/FIFA from Newgrounds? No? Ok.
-Improve the gameplay by giving the character more mobility, no one with a decent taste in videogames is gonna like the wonky controls, also, make the bosses more complex, complexity that will come as second nature if you improve your main character mobility. Also, make the bosses attacks harder to avoid but with way less HP => The battle is shorter, but requieres more skill hence: More rewarding to the player and doesn´t feel like a fucking A button masher.
-Hellmode it´s one hell of idea, I like it, but the only thing it included is a re-skin of the Death boss, a shitty selection-boss run, the bad designed battle against RoboJesus and a joke Boss, expected a bit more than that as a player.
-Change the tittle of your game to : "Crouch and mash A: The game".
Just In case you wonder, I beated the game fully and got all medals. It´s a founded review.
tl:dr: Cheaply made game, easy to beat, could be improved in a plethora of ways. If you made it for fun it´s ok but don´t expect mercy from objetive reviewers.