Very good
At first I thought "Meh, another side scroller?". Decided to give it a try anyway. Lucky me.
So for the first few minutes it was just a typical sidescroller. 2-3 hit baddies and the occasional "How do I leave this room" areas. I wasn't going to quit, though. I wanted to see it through to the end. And this turned out to be the best decision I made for this game. Because that first boss fight was just amazing. There were a myriad of attacks. Not your typical sidescroller. A lot of attacks and ways to evade them would juggle in my mind in a duration of 3-5 seconds per attack of his. This addicted me. What were the other boss fights like?
And, my friend, you did not disappoint. The second boss fight was even better. I was going crazy trying to figure out how to hit him until a stray charge hit those platforms. I was jumping around for a good 3 minutes before I figured that out. Amazing game. Amazing.
It took me 3 tries to beat the watcher's first version. The second version wasn't so tough, though. Maybe you should've interchanged them. Because even their attack styles aren't suited. The first one was more of a "final form" version. The final version would've made a more suitable first version.
And I noticed that you can double jump at certain time intervals? Just a suggestion. Either put an icon that indicates that you CAN double jump again... or just take it out completely.
Other than that, AMAZING job.