Yes there is a tremendous difference between winning in-game virtual items/cash and winning real money. One creates ambitious teenagers, the other creates financial hardship.
At the end of the day no matter how much you slather this in sugar coated shite, all you’re after is a quick buck and you are using an abstracted gambling business model to achieve it.
If a company creats/buys a game, they ofc are after some money.
Does it really matter which way they choose to earn the money?
Isn’t it only important, that the price is fair and the user has some fun with the product(s)?
And if financial hardship is an argument here, then it should be an argument for all those “gaming machines” where you pay per play without having the chance to win.
I mean, we are talking about a few dollars for a handfull of games or aren’t we?
And again, i want to point out, that it sounds like playing a game with the chance to win money is worse then playing the same game wothout a win-chance.
Take this example: On the Website you can play Tetris, 1$ for 1 game.
If you beat the Highscore you can win (for example) 2$. The chance of scoring the High-Score is (for example) 20%.
On another website you can play the same Tetris game, 1$ = 1 game, if you beat the High-Score, your name is on top of the High-Score list, nothing less, nothing more.
While the first one is a “gambling site” the second one isn’t, but for the same number of games the second site is more expensive.
So is the first website really the “bad” one?
Seems like it could mean e-sports - i.e. prizes for being good at a game 
Whether you could get people to carry on playing when they know from their first couple of games they can only get 1% of the high score is another matter. I wouldn’t. Also if there was any decent prize money the games would be cloned and people would practise off-line and only go on the site for a big money high score “attempt”.
I suspect it would impose specific design goals on the games. For example including a lot of randomness (e.g. space invaders where the mother ship awards like a million points sometimes!) - then even a noob could stand a chance of getting the high score sometimes. In which case it would approach gambling more or less closely depending on how random it was. If it’s a gambling site I suspect that’s the way they’d want it. For example all big gambling sites feature poker, but they strongly encourage players to play in variants with quick turnover and high luck factor.
But a game of pure skill played for money? That would just be sport, and the big money to be made there is in access/media, not from the players as such. Broadly speaking sport as such a good thing IMO 
So @OP: Are you looking for largely luck-based games of the first kind, or more e-sport kind of games which might attract people to your site, some just to watch, rather than exclusively play?
I meant, I saw open-source license on almost all projects I saw here (not all of them, for example, Airships: Conquer the skies by Zarkonnen doesn’t provide current source (only very early version)). And I’m well aware of it being impossible to change the owner of rights in some places (which is part of that “Ugh” in my comment. Anyway, thank you for your response.
THank you for all the comments. @richierich We are looking for simple luck/skill/puzzle games with some randomness to it. At first for the first games, then we want longer games where some people just wan to play their fav games vs others. Score will reset on a schedule. We have sold over 30 bitcoins worth of the coin and would like to get this on the go. If anyone is interested in writing some code for us. email me @ simonsez@btcdraft.com has to do with https://en.bitcoin.it/wiki/API_reference_(JSON-RPC)