But maybe that is me misinterpreting the words 'source code'. I thought source code is only needed if you want to change way the engine or its functions works? It now seems to good to be true to create games. Maybe it is not royalty-free otherwise?
I didn't check lately but you indeed did get the full engine for free back then. When looking at the feature comparison it seems that you have to pay only for getting some rather minor physics gimmicks like more than 1 car in its car physics system. The engine itself is free to use - the source code isn't needed to make games with it but it of course is nice to be able to easily do slight changes to the built in features like tuning a shader or influencing the pathfinding to your liking...
Apart from that I think you weren't allowed to earn money with a product developed with the free version which is allright I guess especially when being given the full engine. I'd recommend downloading the
free SDK and give it a try. It really has an extensive amount of demo projects you just can run demonstrating certain features each (there even are some demos you could call simple games)...
