Good concept, seriously flawed
I'm left with the distinct impression that the maker of this game doesn't understand how to play tower defense games. While having a multitude of options available is cool, and the interchangeable upgrade system has a potential to make the game innovative, the vast majority of the choices are so useless as to not be worth buying. In fact, several options (the ones which increase reload rate at the expense of damage) are actually DOWNGRADES for your towers. For an intelligent player, such options may as well not be present in the game.
Worse, the pre-buying descriptions for the accessories are so vague as to lead you to mistakenly purchase a useless item. Not knowing the lifestealing hat has such a low chance of working, or even that it operates on a per-shot basis, for instance, leads players to spend a lot of money for something their tower isn't likely to make any use of. With no way to sell an individual hat, or even to buy a a replacement from a different hat tree, the player is left with no way to recover from the mistake except to sell the whole tower at a loss or to have an effectively hatless tower.
Tips to make the game actually work:
- Rebalance all the accessories so they all might actually be worth it given the proper situation. Right now only the sniper, strong, moneygain, level 1 of the life gaining, and sometimes double/triple damage items are ever worth anything. Increase likelihood of functionality and the general effectiveness of other upgrades.
- As you rebalance, remember that damage per second is king, with a minor bonus to long range (as it increases the seconds during which you deal your damage per second). Right now the machine gun and fast upgrades reduce BOTH. Fix that.
- Make the enemies more varied. Make some waves deliver enemies in a tight cluster so splash becomes better, make the fast waves faster (and make sure the slow effect is actually effective at dealing with them, I suggest the slow effect sets enemy movement speed to 1 rather than a % decrease), and make the average number of enemies per wave smaller so that there is more room for clever use of abilities.
- Replace the level 1, level 2 accessory system with a "you can buy two accessories of any type" system. Maybe then swaping hats mid game would actually make sense.
- The max level per tower needs to be higher.
I hope this helps you to take the kind of innovative accessory system you have in place here and turn it into a game that's actually interesting. Right now this game is, strategically speaking, a boring piece of crap.