I do see potential in dApp based games, assuming of course that blockchain sticks around long enough to make them a success.

It's a different form of serverless cloud computing really. You could, for example, get centralised serverless compute using AWS Lambda and storage with AWS S3 or DynamoDB, but blockchain lets you go *de*centralised for if you didn't fancy paying a private corp like Amazon/Microsoft/Google.

As far as fees go, it really depends on the technology selected. What you describe is a Ethereum-style approach where the users pay gas fees. Whereas on, say, EOS the developers front the fees by staking their tokens for bandwidth to their smart contract, so the app is free for users. Whether there are fees, how much those fees are and who pays them varies from blockchain to blockchain.

Another factor is whether every move actually goes into the blockchain at all, using state-channels you can settle multi-step transactions off-chain with the smart contract acting as escrow and only commit to the blockchain once the channel is eventually closed. This could mean (e.g.) only 1 transaction per session (rather than 1 per move).

13 hours ago, Nerdeveloper said:

since data is persisted forever on the blockchain, someone has to pay for that storage. Every single action a player makes , is data that must be saved to the blockchain. AFAIK all blockchain games require to pay a mining fee for every single move, and this IMO is asking a player too much.

We're using Phantasma chain for out game. Like other PoS networks, their economy is based on 'staking' your coins (basically locking them up for a period of time) and this is used instead of computationally expensive mining. As such, the network is a lot cheaper to run, and the amount of transactions you can perform per second is relative to the amount of coins that you hold. If you hold enough coins, your transactions are basically free. 

You can also either set things up so users have to pay for their own transactions, or so the dapp developer covers the transaction costs.

Storage for smart contract state is also tied to your staked coins. If you buy and stake enough tokens (a one time cost) you get a certain amount of permanent storage within the network (which is only erased if you unstake your coins).

13 hours ago, Nerdeveloper said:

Pros

One of the reasons this hasn't taken off IMHO is that these are mostly pro-consumer things, whereas maintaining tight control is better for a big game corporation that wants to maximize profits... As such, I think you'll see smaller games forging the path here before you see Call of Duty, etc using distributed economies.

As for more pros/cons - you can make the game license itself an NFT, so players can resell their digital games (as is your right in the EU). 

As for cons though... Asking users to protect a private key is scary, as users make mistakes. If they disclose their private key to hackers, all their stuff can be stolen and this theft can't be undone. This means you're unable to provide any customer service here...

On the plus side, being unable to provide customer service means you don't have to provide customer service ?

To avoid the whole private key security issue, you may actually want to develop a secure server that uses traditional passwords and 2FA and stores private keys (in a HW module that prevents their theft) on behalf of users for a better UX...

26 minutes ago, Nerdeveloper said:

it would be impossible to see a Replay of the past game sessions, since the blockchain has not all the required data : all moves should be saved for that

We had a big discussion about this in the discord this week ?

If your game is deterministic, you can include a replay file of a realtime (non blockchain) game session as part of a transaction, and a smart contract could validate that this replay file is legitimate before allowing the results from that gameplay session to be committed to the chain.

That allows your game-state to exist as a distributed, secure database, but also for non-blockchain real-time game servers to handle all the fine grained logic, and to have fewer, large transactions.

You can also have this replay verification step be performed "off chain" and then get the results of that determination into the smart contract via use of an "Oracle node" in the network.

As for monetizing - instead of representing game items as NFTs, you can also store them in some internal format within a smart contract instead, which prevents players trading them. You can then charge players a "withdrawal fee" to remove the item from the smart contract and convert it into an NFT (allowing the player to trade it). If you're doing 2FA, that's probably also a good point to place a security check to prevent theft ?

Alternatively,.some networks allow an NFT to be marked as non-tradable, and you could charge a fee in your game when players want to convert it into a tradable NFT. You could use either of these to also gain some income on 2nd hand sales if you were representing your game itself as an NFT.

16 hours ago, Nerdeveloper said:

Your dev team's node is the only one that can write the transactions, or fail to do so

That's not how proof of stake / dpos works -- From a high level view, it doesn't massively change the way that transactions are added to the chain from the typical POW systems (the "miner" is just chosen differently).

i.e. Typically your dev team only runs test nodes on a private test network so that you've got full authority to pull fake money out of thin air for testing purposes.
The actual decentralized blockchain network has it's own nodes that can each take on the responsibility of processing transactions (POW = a miner solves a hash puzzle, POS = a miner wagers money that their transaction validation is correct - and anyone who can show their validation was fraudulent can claim that wager). If any of those nodes fails and drops out of the network, other nodes can take on the responsibility for them... With DPOS there's a smaller number of "elected" nodes that can fill these roles rather than it being a free-for-all, but those elected nodes are still interchangeable in the case of failure, and don't have to be affiliated with any particular app.

2 hours ago, ConorH said:

what ties you to a particular asset? I get that the blockchain entries wont change, but how do you own a given blockchain entry? What if someone else claims it's theirs?

The assets belong to a wallet. You can prove that you're the owner of a wallet by signing something (anything) with that wallet's private key. To "log in" to a game using a wallet as your ID, the game sends you a random string as a challenge, you sign it using your private key and send it back, then the game can check whether your response is legit by using that wallet's public key.

10 hours ago, conq said:

Most of the issues mentioned can be mitigated with periodic hard forks.

If your network allows one user to perform hard forks unilaterally, on demand... then it may as well be a centralized system under that user's control.

2 hours ago, ConorH said:

Wouldnt you need to code support for this? Just like traditional games? Could I load the skin for my assault rifle into my chess simulator with no additional code?

Yeah for the items to have an effect in your game you need logic for it. e.g. you can piggyback off a popular game by implementing support for that game's items to do something in your game.

However, you can display an inventory list, show marketplace listings (auction house, etc) without coding specific support for each game/item.