I'm going out on a limb and assuming it's the plan... but, more enemy types would be awesome! Perhaps to pad the gameplay a bit, you could even reintroduce old bosses/boss minions into the waves after they are defeated (appropriatly scaled of course)... Harpies with flight (temp invincibility frames ), Nagas (could interest the vore community), immobile plant enemies or traps could serve to limit mobility; not to mention minitores, orgers, ect. who could deal physical dmg while they fuck you.... The optionss are limitless and, i want to help :D!