Here is your review:
Playability:
Jumping from pillar to pillar was disorienting. The area wasn't detailed enough to easily gain cardinal orientation when swapping pillar perches. Mouse sensitivity issues prevented engaging distant pillar unlocks. Weapon fire cooldown was harsh and felt largely unrecoverable at current difficulty curve. You had to get every shot to hit every time and count to stay on complete pacing. I'd say this felt like a very hard mode at the current state of play. Switching with A/D was not intuitive, maybe moving the mechanic to pointing and right clicking for ease of use.
Cleverness:
I really liked changing the gameplay like this to positioning POV focused than AoE coverage, I could see maybe this being mixed in a bit with traditional Tower Defense mechanics. There's an old LAN Party big team battle game favorite of mine called Savage XR. That used Co-Asymmetric gameplay. Each side had a commander in a RTS view, and the rest of the team in an Action 1st or 3rd person POV and class character or vehicle. Though it might be worth a look, https://www.savagexr.com/
Artistic Style
Art style was not varied enough when applied in design of map, not able to maintain cardinal directions/dizziness from gameplay and POV jumps.
No setting to adjust sound/SFX levels. Was harsh hearing both the music and the melody play simultaneously. FOV slider up to 120 for those like me that get nausea from low FOV games.
GDD:
For a game of this genre, I was curious what diagramming was made in preparation for development, but didn't see any available. I liked the direction of the Upgrades system as described, but was not implemented in the build provided as far as I could tell. Further development could really benefit from fleshing this document out fully before development. It's a great concept I want to see developed on, refined and tuned.
But you did it, you made a complete prototype and it communicated the mechanics you were envisioning! Glad I got to play it and get what you're trying to do! It just needs time. Keep at it!