Cool game! I really like the main puzzle concept, and the additional mechanics like tiles that spawn more followers. The sound and graphics are all great too, and I like the interpretation that the followers follow your actions (with their own twist) rather than your position!
I do think the level designs could be a bit more interesting: the merging mechanics feel like they have good puzzle potential, but you can win most of the levels by taking the shortest path to the flag, then moving backwards and forwards a little to force followers into spikes (or each other) until you have the right amount. The levels without an excess of followers, such as Level 5, avoided this issue and were the most fun to solve!
The input handling could also do with some polish, because moving twice fast can desync the followers from their intended positions, or even teleport you about (try pressing right twice at the start of Level 8). There are some other problems too, like being able to move well before a level loads, and after you die or complete it. And if you press two directions at the same time, then the followers move in a different direction from the leader...
Overall though, I did really enjoy it! I'd love to see more of this game, especially with more puzzles like Level 5 that have tighter solutions :)