Unity 3D sucks. It's a huge game engine and editor which aims to bring noobs like you the opportunity to create a very bad game. It aims to be simple to use, yet it uses C#-Style scripts and uses Capital Style Variable Names So You Can'T Fucking See If Something Is A Variable, A Method Or A Class.
Also it's physics engine is buggy like hell. If you finally get it to work (almost) like you would need it, it stops working randomly once you go out of debug mode. Since you're not in debug mode anymore, you can't find the source of the error. Once you switch to debug mode, the bug is gone.
And when you finally did something that could be a game, and spent hours building levels and scripted objects, you decide to add some fancy graphics and they tell you anything that doesn't look crappy has to be made with a pro license.
Examples: Shadows need a pro license. Being able to work at a project in a team needs a pro license. Render-To-Texture needs a Pro license. Importing Blender meshes doesn't need a Pro license (but it doesn't work). Video playback needs a pro license. Even another skin needs a pro license. The "Pro" Version is just "1500$". (Basic) iOS Support costs 400$. Basic Android: another 400$. "Pro" iOS and Android each cost an additional 1500$.
I suggest everyone who wants to use Unity 3D to do something serious to find a wall and bang your head to it as long as you still think it's a good idea.