The music was great, platforming felt very nice, good animations, great pixel art, and everything fit under a cohesive art style. However, the game was very difficult and unforgiving, or maybe I'm just really bad, but having to play the same exact level over and over was really frustrating. Besides that, though, this is probably one of the best entries I've played so far.
Viewing post in Into The Core jam comments
Thank you for you kind comment, we actually thought long about the difficullity of the game. but in the end, it is actually no that long, so we decided not to include checkpoints. We wanted to reminiscent old platformers, that were unforgiving, hard and beating them gave you satisfaction. I am very glad that you liked the rest :)