Estimated time to 100% - Less than 1 hour.
How to 100% It Faster
Single Player -> Slaughterhause -> Select Redneck class and do as I did on the screenshot below:
You can put a tick on Enemy Hp bar (not sure if it's ticked by default).
- Cooldown time = 0 (just few secs)
- Difficulty = 0 (easiest)
- Wave size = max (40-ish enemies per wave)
- Number of waves = this doesn't matter much* but you can set it to max as well
* - It doesn't matter because when you beat wave 1 or while you're still at it it will be night time already so it's better to just restart the game.
When you start the game look for weapons. There should be a few at a place (they will be marked with yellow outline). Pick up ak47.
Look for any door marked with red outline. Enter it by staying in front of it and pressing "E" button when the hand cursor appears.
What You Should / Shouldn't Do
- ✓ - Play only while it's day time (optional but recommended).
- ✓ - Play versus faster moving animals (like stags / foxes). If you start the mission and enemies don't spawn in 1 min or less just click restart. Some animals (like giraffes) are really slow so you will get achievements at a slower rate too.
- ✓ - Use stronger weapons (such as AK47).
- ✗- DO NOT play till the end of the game (a.k.a. fight bosses as they only award you with 1 achievement when you kill them and are much harder to kill).