A colleague just switched from a game development company to our gig, which is selling Field Service Management Software which integrates with SAP.
So we talked a bit about the differences and I hope this answers your second question.
1. Constant Updates/Upgrades
Most games are a one time effort with some patches and maybe a add on and if it’s really successful a sequel.
Business Software runs for years in a company and needs to be supported. So the customer needs to sign a service contract besides the initial payment and licenses. Games are usually a one time buy. Exceptions are MMOs. Game companies noticed this mishap and are trending to service games now, which would create a steady inflow of money from loyal customers.
2. Complexity
It depends on what the game company focuses on. If you only build games, you need to master a game engine or build your own. It doesn’t need to be customizable if it stays in your company.
With ERP software you need a lot of configuration switches and cover a lot of similar but not same use cases. A standard product is almost never bought my businesses. They want you to build something for THEIR process.
So what SAP did is maximize on this need and they built so many customizations, that you need special training to even begin to understand one of their modules.
ERP is definitely more complex in the realm of more stuff to learn and to remember to get it right.
In terms of complexity defined as difficult I can’t really tell because of my lack of experience with game development. But I guess mastering a game engine is difficult, but less “complex” than ERP software.
Funny side note: I did a SAP training one and half years ago at their HQ in Walldorf, Germany. And they own pretty much the small town. There were so many foreigners in town to visit SAP. The SAP campus had the same size as the town :)