Bouncing between spikes while avoiding two spinning spike balls... with these controls? Nope. I'm sorry, but there's a difference between difficult and absurd, and this game did the second far too many times. For example: the level where two sets of three lava monsters shoot up, and the treasure chest is up top. The level itself would only be hard because you require the player to jump perfectly because of the ceiling, but by sectioning off the treasure chest the way you did, you ensured there would be at least 15-20 seconds between every attempt, turning an otherwise meh difficulty level into a test of my patience. The controls are too twitchy for a lot of the crap you ask for in these levels, and the lag that started happening didn't help either. I took steps to make sure it wasn't just me, and nope, still lagging, especially on levels with a lot more lava and such. But even assuming lag wasn't there making me have a 10 percent chance my button press won't be registered and I'll die, the other stuff is just too annoying. I love platformers, and I've liked other games of yours, but this one wasn't enjoyable. It didn't even give me satisfaction to beat the levels because they were just so frustrating that I rarely felt like it was my fault if the level took me a long time, instead always noting a couple of design flaws that made the level arbitrarily more difficult. The art, music and general aesthetic were nice, though the art conflicted with the pixel level precision required for some parts. This is one of the few difficult platformers where I've stepped back and said "I am not enjoying myself in any way while playing this, and beating levels feels hollow instead of triumphant... I'm going to stop." And then proceeded not to play it anymore.
TL;DR: Game controls are twitchy, art and music are nice though art conflicts with gameplay, difficulty seems arbitrarily high via poor design. Workings of a great game trapped in an unenjoyable one.
On the plus side, your other work, out of what I've played thus far, is good and enjoyable enough to provide the perfect transition as I leave this game behind.