It's cool. The movement feels pretty good, even if some jumps are very tight. I've been looking forward to trying the demo for a long time, and finally got around to it this time. The level designs are quite compact, and you were able to do a lot with just a handful of mechanics. The game has excellent visual presentation.

I did have a lot of controller issues. I play with a Switch pro controller generally, which I use through the Steam controller configurator (since it's not XInput) by adding the executable as a non-Steam game, which usually works fine. For whatever reason, the standard setup with that caused the inputs to be read as always pressing the Up button. Although Jump worked fine, I couldn't input any directions. That in itself might be worth looking into since you plan on doing a Steam release.

I changed the input settings to use the preset template for Keyboard to Controller, and that let me play, but it constantly misread the up button while pressing left/right (since I played with the stick). This caused me to constantly accidentally drop the bomb out of my hands. This was a huge source of frustration and caused probably around 200 of the 600 deaths (!!!) I had by the end of the demo. If you don't end up doing remappable inputs, I would really like to see the bomb drop key remapped to a non-directional button/key. Any other button would be fine, just not Up.

Having what in most games is the pause button mapped to "immediately exit the game" is hard to get used to. Even just a "Quit? Y/N" prompt would be fine.

The music stopped looping on floor 16. Not sure how long I was playing to reach that point.

You can also make the floor unwinnable without killing yourself on a few stages if you drop the bomb in one of the vertical screen boundary warp shafts (floors 16 and 17, and I remember there was at least one more later on). The bomb falls infinitely without despawning if you do that, and it also picks up infinite speed.

It was fun to see the character get increasingly frustrated as the death counter went up - it's a great touch. You might want to add sprites for that while also carrying the bomb.

I also wish the splash screens between stages lasted just a little bit longer, but I get why they're quick.

Thanks for uploading. I look forward to playing it again later on. Nice job.