The Bridge of Evil level in general, but especially the boss fight against Glutton Train. This is a unique timed level that teams Miriam and a CPU-controlled Zangetsu up (the first and ONLY team-up in the game) which makes the player feel like a Badass Duo. The boss fight is then extremely cool and unique in that surviving its patterns involves using Zangetsu himself as a mechanic.
The regular enemy Tamako-Death who is essentially a demonic rocker chick that shoots fireballs and uses her guitar as a flamethrower. Plus once you get her shard, you gain the ability to summon her to do it for you.
Fighting the Bonus BossO.D... and by fighting O.D., we mean fighting Alucard in all but name and color scheme. He packs most of his old moveset - he can turn into a bat, a wolf, or mist, he's as good with a sword as ever, and he even keeps the classic three-fireball attack. To a veteran Castlevania fan, this fight alone can make for a Moment of Awesome.
A smaller scale one with the Backer goals: one of the early tiers for achievements was to reveal stretch goals early. The project went through the stretch goals so fast they had to redo this achievement because they'd already had to reveal nearly every stretch goal.
Managing to get Robert Belgrade, Alucard's original English voice, out of retirement to voice a cameo role in the game.
YOSHITAKA AMANO is doing illustration work for the game. $800 for Amano's signature on the poster. 10 were available. They sold out in ten minutes. It was so popular they added more for $950, then a third set for $999! And, as a final act of awesome on both the team's and Amoano's part, anyone at a $1000 tier or more will have their poster signed, doubling as a heartwarming moment. Yep. These guys love the fans all right.
Update #19 showed a very early build. It wasnt much obviously, but the fact that the team made that in just 2 weeks, and that it looks just like the concept art, went a LONG way towards assuring fans their money was well spent.
On June 9th 2015, 3 days before the Kickstarter period ends, Bloodstained managed to surpass Mighty No. 9's Kickstarter fund amount of $3,845,170. A day later, they hit the $4 million mark. A day after that, it managed to become the most funded video game project on Kickstarter.
On June 12th, the final day of the Kickstarter, with hours to spare, the project hit 5 million. What is the reward? A bonus Roguelike mode. The team even needed to come up woth a new $5.5 million stretch goal (a mode where you play as Bosses and become a Hero Killer) and a 60 backer achievement for a new costume for Miriam, showing what she was like pre-curse. The $5.5 million stretch goal and 60 backer achievement were achieved with over two hours to spare. The final amount for the Kickstarter? $5,545,991. This isn't including the Paypal funds, which put the project to roughly 5.75 million.
Fangamer deserves massive praise for the KS campaign itself. Excellent PR, perfect buildup, partnering with various YouTube personalities, a unique achievement system to tie into social media etc. The success of the campaign speaks to the quality of their work. The fact that IGA and his team avoided most Kickstarter pitfalls during development and closely listened to fan feedback before release. Graphics and lighting not up to snuff? Call in WayForward Technologies to give it a polish. Backers disappointed with cancelled ports and unimplemented features? Make the DLC free to all. All this may have caused the game to be delayed, but it was worth it in the long run, because IGA refused to disappoint people by releasing an inferior product.