Silent Hill based questions

I would like to say ahead of time I AM NOT saying im making a game cuase im still kind of a beginer with the game engine but through this game project i hope to learn alot instead having a bunch of random tutorials i would like to have one project to focus basic but important things and common things. So here are some questions ANY tutorials or answers would be lovely and i definitly need help with blender python scripiting im VERY weak in that department which i know is important so anyways here are a few of them.

1.How to have an inventory. ((im looking into the right now))
2.How to have a key item suck as a key to open a door.
3. AI system
4. Having Ammo
5. creatures health ((i know this one includes scripting))
6.How to make diffrent scenes not reset the game (( like erasing everything in the inventory when you go through the door and it loads like a whole new level))

so basicly this game is HEAVILY influenced by Silent Hill and im not sure if i will ever finish it but if i do i will be happy to post the short level demo for free so all can enjoy. Thank You!

Learn to use Properties and you’ll probably be able to figure out all the answers yourself.

Check out blendenzo’s website and also Social’s FPS template.

Thanks for the support guys!