I'd say this is a fine little platfomer. It provides some decent challenge with some of the precision jumps with the spikes at the end. I did think I left the rising acid behind a little bit too easily...
Also, for some reason, both A and D and the Left and Right Arrow Keys can be used to move left and right, but only the W key works as jumping. I thought it was weird, but it's not too much of an issue.
Some more presentation notices:
- The spikes could look more prominent - the first time I walked into them thinking they might be part of the scenery
- The player character could use some walking and/or jumping animation to look more lively
- Some of the pixelart seems a bit blurry? You could check the filter for the images is set to point/none