The best Unity and game development tutorials I've found, both written tutorials and video tutorials.
A very informative and easy to understand video tutorial by Sebastian Lague on how to implement and optimize A* pathfinding in Unity.
An awesome video tutorial by Sebastian Lague on how to create procedurally generated caves using cellular automata and marching squares.
A tutorial series by Sebastian Lague on how to create a top down shooter with a really cool procedural map generator.
A fantastic 5-part written tutorial series by Alan Zucconi about shaders in Unity. For developers with little to no knowledge about shaders.
A written tutorial by Jasper Flick on creating a procedural maze. One of the best written tutorials I've ever read and the result is practically a fully playable game.
A written 10-step tutorial by Derek Yu on how to draw pixel art. Very informative and easy to follow.
A written tutorial by Rafal Wilinski on how to create an animated particle sea effect in Unity. Shows how to manipulate a particle system through code and how to use Perlin noise.
Recently a VFX artist named Kevin Leroy posted a bunch of fan-made League of Legends ability effects made in Unity on Reddit, and they are easily some of the best VFX I've seen in Unity.
Assets like image effects, tools, models, textures etc. that you can just drop into your Unity projects.
The best antialiasing currently available for Unity if you're using deferred shading and it's completely free and open source. Created by Thomas Hourdel.
A completely free and open source screen space reflections image effect created by Ben Hopkins.
Brilliant looking volumetric light effect which can be used to generate lightshafts on directional lights and spotlights. Created by Robert Cupisz.
A seamless editor extension for Unity which gives you very intuitive handles for editing 2d joints. A must have if you do any work involving 2d joints. Made By Firtina Ozbalikci.
A Diablo orb shader created by Mourelas Konstantinos. This effect looks practically identical to the health and resource orbs in Diablo 3.
4 different approaches towards making some great looking outline, selection or highlight effects in Unity.
A really cool shader by Ronnie Moe. Just throw this on a plane and you have water which looks like the water in Monument Valley.
Vision cone created with a procedural mesh. Can be used for enemy line of sight, cameras etc. Made by Ben Redahan.
This asset, made by Ryan Nielson, ensures everything in your game is aligned to the pixel grid at all times.
This post processing effect made by Pavel Dobryakov perfectly mimics the frosted glass look used a lot by Apple in both iOS and OS X.
Tips & Guides
Articles and videos related to game development which are not complete tutorials, but are very useful nonetheless.
A fantastic article about actually finishing a game by Derek Yu. Useful for any up-and-coming game developer.
A really cool article by Artyom Sovetnikov about implementing blend modes like overlay, multiply, color dodge etc. in Unity.
A short, but very informative video by David Rosen on one way to approach player detection in a stealth game.
An amazingly detailed breakdown of the graphics in Grand Theft Auto 5 written by Adrian Courrèges.
A fantastic talk by Adam Noonchester on how the AI for the enemies in Sunset Overdrive was implemented.
A very detailed breakdown by Simon Schreibt on how the mushroom explosions in Fallout 4 were made.
An article by Simon Schreibt on how to create lens flares using vertex colors rather than textures enabling them to be scaled infinitely with no loss in quality.
A great talk by Bronwen Grimes about creating the content needed to drive an economy for Counter-Strike: Global Offensive.
A great GDC talk by Jane Ng about making a big open world game in Unity as a small team and the challenges associated with that.
A great article by Derek Yu about how Spelunky on XBLA came to be.
Old official projects
These projects have been removed from the Unity Asset Store and the official Unity website because they are
not longer supported. I'm hosting them here because I feel there are still a lot of value in them.
Disclaimer: These projects are no longer officially supported and they are NOT for Unity 5. Most likely you'll get no support from me either, just use take them for what they are.
The original first person tutorial. Probably not the most useful tutorial by todays standards, but it features an entire level, some neat models and scripts.
Fairly outdated by today's standards, but there are some neat things in here like the cool particle effect for the rocket or how to use trigger colliders to produce footstep sounds.
This tutorial project is asset heaven. It contains a complete modular level suited for making a game in the style of Little Big Adventure, Ratchet & Clank, Crash Bandicoot, or whatever really.
This project is still available on the Asset Store, but for how long? I'm hosting it here just in case. It's an excellent project with a lot of value.
My favorite Unity example project. The character model is excellent, but so are most of the assets in this project and some of the scripts are really useful.
Outdated by today's standards, but the track itself is fun to play around with and can be used to prototype a racing game. The car model is also pretty neat and there are some cool scripts.
Here's a list of additional resources which I either haven't had the time to actually sift through yet or
they are just too comprehensive to put in one of the above categories.
A ridicoulous collection of spectacular articles by Amit Patel about algorithms related to game development. His interactive examples are mind blowing:
A steadily updated blog by Jonathan Parham about game programming with a lot of articles and tutorials about creating systems for RPG games:
A list of all the tutorials and articles by Pixelnest Studio and Damien Mayance:
The unbelievable Unity assets of Keijiro Takahashi, a game developer and software engineer currently working for Unity:
Even though I've featured one of Jasper Flick's tutorials he has so many more and they are all amazing so I'm listing him here as well: