Great concept, really works the mind to try to memorize how many times you moved. Very original. Somehow reminds me of minesweeper though, just hoping for luck.
This is why math is useful, kids. Mathematically, if you alternate colors, four can cover any shape you design, because you cant have five shapes sharing an edge.
Possibly add a co-op multiplayer mode where you can band up with friends. One of the friends controls the AI placement for your team, and the rest of them can control their own characters and shoot a character chosen at the beginning. Also, an interesting idea would be adding an option to play as the alien team. 5/5, Favorited, Shared.