Thank you for your honest review!
I agree that the map design may be overly complicated in some parts.
However, the building order still has some alternatives. Yup, the Apothecary is the best builder assistant to start with (cause of Alchemy Tower's gold bonus). But aside from that, various builds should work, as long as you have enough slowing and anti-spell casters stuff.
I keep dying at random levels
I assume the non-boss rounds may be difficult due to frost armor /inner fire creeps' buffs.
One can plant a Cannon Tower's EMP mine into the creep caster pack, so their mana and buffs are gone.
Or use the Arcane tower to dispel these buffs.
Or get some upgraded (Tier II-III) Plague Towers and Cannon Towers (Incendiary Bombs mode) - their spell damage ignores the creeps' armor.
Or get a combination of these variants.
As for Round 20, as far I understand, the trouble was in Inferno that won't let the boss hit points fall below 30%
One can use the Citadel's Silence spell to stop the Inferno's healing spell casts and try to nuke the boss (that silence lasts 30 sec).
Or just kill the Inferno first and then finish the boss.
sometimes my towers get a damage debuff right off the bat
Indeed, each subsequent difficulty level has one of four random creep buffs or tower debuffs. Their purpose is to add some variability and slightly alter the proportions of different tower types.
If you have any suggestions on what specifically needs to be removed/weakened/added/strengthened - please let me know!
Or maybe you could send me a replay, so I can figure out what exactly I have to nerf.
For now, it seems I should make the towers auto-target the Inferno for easy mode as well.