the idea of paying for the sets to unlock the campaigns is spoiling the fun. Without the unlocked sets it is merely a demo. You should make most of it free and only some e.g. newest sets should be avaliable for kreds. The game could have 4/5 raiting but as most other players i rank it 2-3/5
a skill tree would be nice. Whenever you gain a lvl you could pick up a skill. different weapons would also be nice. and make the game a bit longer. It is a fine pice of fun m8.