Love your take on the theme, the mechanic of gathering ocean scrap to build a wall against the onrushing tide was a really good balance of tension and exploration. I was able to cheese the game in my first play through just by holding down the right arrow and finding my alien body lol. It was a nice gamer moment. Some tweaking to the difficulty and a bit of playtesting by others could help with this sort of thing in the future. The alien guy is a cute character and the dialogue added a nice amount of personality but I think a more consistent artstyle would help the overall aesthetic alot. Using a cohesive color palatte (try Lospec for ideas) and the same pixel size for all the sprites would help a lot. That being said, I had fun playing your game and I think it is 5/5 for theme. Keep up the good work!!