The character design is the overall structural support of the Haydee franchise, even though Haydee 2's protagonist looks more human (and probably is) than robot.

In Haydee 3, Haydee (or, more preferably, HayD) has 2 different designs:
- HayD 01 (Breasts, vagina, ass)
- HayD 02 (Breasts, penis, ass)

HayD 02 has penis flop physics and breast and ass jiggle physics.
HayD 01 has breast and ass jiggle physics.

HayD resembles more of Haydee 1's character with more muscularity.

Haydee 1's enemies felt, well... lacking, in my opinion, while Haydee 2's enemies felt more better ;)

Slashers and Creepers make a return, and some ♥♥♥♥♥♥♥ made a walking kamikaze mine. It has robotic spider legs and is the size of a regular mine. It's beep speed depends on how close it is to the player. If it's far, it's beeps are lengthened, but if it's close, it's beeps are more rapid and once it's in good range of the player, it has a 3 second "long beep" before it explodes, giving the player a few seconds to run away from it.

While walking kamikaze mines sound bad, wait until you encounter the Untoter, a bulked up creeper that patrols hallways and takes 30 shots to kill. You can use closets and conveniently sized lockers to hide from them. Stealth is a good approach since it only navigates by sound. It looks familiar to Doom Eternal's Hell Knight, but of course, more Creeper styled.

These objects are of no helpful use but it does provide some schmexy scenes.

These objects include:
- Sex doll (HayD 02 only)
- Vibrator (HayD 02 [ass], HayD 01 [vagina])
- Beds that can be found in private rooms (used to regain stamina or just lie down there for fun, provides a sexy rest animation)
- Body pillows found on the beds you can cuddle up with (♥♥♥♥♥♥♥ weirdo)

Private/R&R rooms can be found anywhere in the facility, from level 1 to the very last level. These rooms include:
- A table with medkits, ammo, and guns
- A bed with a sex doll
- A couch you can:
* Press F to lay on
* Press E to sit on
- A vent that circles squares around the room and exits in the same room, just in a different place
- A workbench you can use to add updates to your guns, armor, and even yourself (better armor, double jump, etc.)

I was disappointed to find out that both Haydee 1 nor Haydee 2 have free roam, so I hope the developers add free roam in Haydee 3 that lets you explore (supposedly) HayD's house. It's basically just a r&r room that has a save slot area, bedroom, bathroom, and stuff that houses have. It's a 2-story house. You can go into the backyard where it's sunny outside and no clouds in sight. The only barricade is a fence where you can see houses behind it. There's an in-ground pool surrounded by a cobblestone patio you can use to swim.