Thanks! I thought I'd leave more detailed feedback.
-Level select from the start or unlocked earlier. As a player I couldn't get a feeling for how long the game was and there was no stopping after 3+ worlds. I couldn't tell when it would be safe to take a break or how long the next level would be. Is the ship hub supposed to be the end of the game or just a milestone to continue with what levels are added?
-Options in main menu for full release
-More content/levels/gamemodes(like time trial) for full release.
-On the ship access my progress of collected secrets
All the above feedback are just nitpicky and no big deal, personally I find the game is PERFECT except the difficulty spike below is the only thing I'd change:
There was a particularly challenging part on the ice level that I think could stop a few players from continuing because of the sudden difficulty spike. There was a checkpoint before 3 screens of puzzles. You progress DOWN to get to the next screen. The first you had to jump (to the left) to reach the middle on top of a Crawmite and the jump activates a spikey-dude that falls to the (right) of you and enables you to go left and down to reach the next screen. The next screen is the large bounce-jump from left to right. The final screen is the puzzle with 3 spikey guys to trigger so that you can proceed.
Individually these puzzles aren't too hard but for 3 screens you can't make a single mistake. And the 3rd and final screen is a puzzle you have to slowly learn after each death AND THEN get back to it to try again to solve it. I couldn't tell you how to improve this issue or if it's intended, perhaps another checkpoint so we only have to go through 2 screens. I love working through these screens though, it was challenging. But the difficulty spiked out of nowhere, did I access a secret path?