Gameplay feedback:
- The Milkman (or a new character based on him) should increase the buffs to two and three persons behind when leveling. This would enable combos like Milkman + [Tank] + Stoner + Assassin.
- Cursing the king does not work, at least not a second time.
- Running out of slots is irritating, it would be nice to have a separate inactive slot just for leveling and combining.
- Ability to unlock an extra active slot on a lane would be nice.
- When getting an entity to lvl 3, a current lvl + 1 entity is added to the selection area (top right). When the top right slot is occupied, nothing is added, which is irritating.
- The Mage is complicated to use, if you cast multiple spells, Mage only charges once. Maybe Mage could cast from given spell books randomly, or behave differently from other ranged characters. E.g. Mage could shield or buff neighboring character in adjacent lane.
- Further ideas: Flying characters (attacking the rear or going straight to the tower), area/splash attacks, "on death of other character" effects.
- Some sort of progression and different challenges as you wrote would be nice for replayability.
- Didn't know how to make the game on Windows fullscreen, window was quite small. Mac build would be great, dunno if this is easy or possible with GameMaker.
- Are you looking for collaborators? I would be interested in porting it to Unity.