Slow doesn't slow anything, splash damage is nearly worthless. The only tower really worth upgrading is cannon.
Once you complete the game, you get points for placing towers.
Sound would be nice.
Enemies could use some variety as well.
No info for weapons, can't restart game because weapons disappear, but space remains blocked, some vehicles outrun projectiles and towers track target but won't fire.
 "Epic war"){kind=icon}
 "Chibi Knight"){kind=icon}
 "Truck Launch Maniac"){kind=icon}
 "Dream World"){kind=icon}
 "Warlords: Call to Arms"){kind=icon}
 "Tower Defence (random!) UPGRADED"){kind=icon}
 "Shadowreign RPG"){kind=icon}
 "Easy Tower Defense"){kind=icon}