It looks very nice, the animations on the main character are fluid and well done. On the whole I liked the audio, although the explosions were a little harsh and could be heard across the level, I wondered what the noise was at the start.
Some prompts with the controls would be useful. I didn't realise until about halfway that you could double jump (I managed to walk along the edge of pit) and it wasn't until I saw the comments that I learned about the gunplug, I pushed Q but couldn't figure out what it did, so just assumed it would come up later.