There are 16 achievements to get within this game - and in my opinion - the "Crazy Spermicide" Achievement is EASILY the hardest! Loading up $50,000 is no problem; but killing 500 of your own kind??? Yeah, that's gonna be hard - not to mention that only ~1,000 sperm enter the uterus initially; and you have a limited distance to travel to kill about half of those sperm. So, how can you possibly get this achievement???...there are other guides that say the gist of it, but for those who need a more detailed explanation as to how to get this crazy-hard achievement; I shall help you the best I can...so without further ado, let's begin :P

Firstly, you should know that there is a weapon called the Uber Cannon; which can be gotten by being the first sperm to get digested. How do you get digested? Well sometimes, you somehow go through the wrong hole and end up landing in the stomach. So just do what you do to conceive an egg - aka using this loadout:
At some point you will see a brown-ish barrier instead of the usual egg cell. This is great! So zoom into there right away, and if you're in first place, you'll get yourself an Uber Cannon! :D

Now this is the part that's actually hard - killing all the sperm while also considering the conditions given to you. The first time I got this achievement I used this loadout:
Now just keep holding down left-click as your Uber Cannon homes in on all the sperm it can, and focus on grabbing the hearts and energy bolts somehow lying around in this deep, dark passage...keep in mind you don't have to still be alive even after you killed 500 sperm; all that's required is that you kill 500 of them, and that's it; as shown the first time I got the achievement! 8P

So...yeah; this was my very first Steam Guide, so - hope you enjoyed it, and I hope it helped you get this crazy-hard achievement! :P