Great game! The concept, visuals, and gameplay are pleasing and fun to play around, and music & SFX are on point.
As others have mentioned, when players rely on trial-and-error to complete a puzzle game—it takes away the fun and its frustrating. Also, although the concept of teleporting to previously placed down flags is neat, it has little to no use in this game besides a few levels... perhaps in the future more levels could include this cute-simple-fun core mechanic.
All in all, great work!