I finally played through Castlevania - Simon's Destiny! What a crazy ride!
I would like to share my experience with the game, positives and negatives in points. Warning, the post is pretty long!
Positives
+Level design is great! True to the source material, nicely translated into 3D
+Nice level textures, spooky fog effect, nice usage of colors and lighting
+Lots of candles to destroy, meat in walls, nice variety of enemies from the original game, plus extra enemies in Bloodmoon mode
+Only six levels like in the original game, but they're nicely extended and long enough.
+Whipping is fun, but also subweapon usage is strategic and essential
+Great soundtrack!
+Good sound effects.
+THAT AVGN REFERENCE! OMG!
+Medusa heads are not that annoying!
+Needs some backtracking because of keys, extends the levels nicely, BUT...
Neutral
/You can get subweapons accidentally, replacing your previous one. Not a big issue, it was the same in the original game too.
/Most of the enemy sprites look great, but I felt some lazy. Got from the games without modification, not facing to the main character but in a kinda side view. (Actually I would love to help with additional sprites if you plan to release an update in the future)
/Sometimes it's hard to judge the length of the whip, not sure how it could be fixed since it's a 2D sprite. Usually not a big issue, but in case of smaller enemies, it's harder to get the distance.
Negatives
-Hit detection kinda feels weird, constant damage is strange, no invincibility time. I don't know how it would translate to 3D, but some attacks are really inconsistent, when it comes to damage. Like the axe, it can damage enemies a lot, or just barely, depends on how long it is in their hitbox. Attacks like what Dracula uses, like the lighting can kill you easily if you stay there, but sometime it barely damages. Bats and other small flying enemies are harder to judge when they are attack from, sometimes they literally suck lots of HP, no indication from the attack direction. I wouldn't mind higher damage, but with invincibility frames.
-Sprites in Bloodmoon are from Symphony of the Night, many of them kinda feels out of place compared to the others in style.
-Some enemies have ridiculous reaction time. Like you just open the door and you already got hit. Especially annoying in case of the skeletons that shoot beams from their dicks. I mean, it looks like it.
-Backtracking itself is nice, but I wish, getting a key would spawn some new enemies in the already cleared areas.
In overall, fantastic game with a satisfying ending. Challenging in every difficulty levels, and it feels so rewarding, when you complete a level. Wonderful level design, great graphics (I used a retro shader simulating low resolution and less colors, just looked so old-school with it!), fun gameplay except for the mentioned negatives. A thing I didn't expect at the end. That AVGN reference was beautiful, I almost died laughing. Really true to the original game, a wonderful tribute, thank you guys for creating this. Really, you are talented! It was an emotional rollercoaster to play it through, but totally worth it in the end. If you fix some of the mentioned issues, it can be even better, but it's already a wonderful game.
Final rating (can change)
8.5/10
My playthrough. Some levels will be uploaded later.
Retro screenshots:
, I found some of the platforming a bit difficult at first, but once you get used to the jumps, things become easier, I'm sure that the flying enemy sprite alignment can be improved, since that could be the cause for the difficulty of hitting flying enemies in general 
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