There's a lot of room for improvement. Hopefully you improve a bunch, we might get a true GTA Flash game on newgrounds, since this was posted recently, im assuming your still alive/active.
- You need to make the city more detailed as it just looks like something made in MS paint, no offense, but that's how I feel. You can improve this by making the city feel more alive by adding restaurants or buildings. You can also make the streets wider and have details like making it black, rough, and adding white/yellow bars. And also building a universe and story behind the game. You can also add walk noises to each area I go to, like grass, or on the sidewalk. Give the game more story and interiors such as a gunshop, your house, or a bank.
- Guns, weapons, and features. You see all you have is a magical thing that kills everything, what is that? Add actual weapons such as guns, baseball bats, and more. Related to my other suggestion, make these incorporated in the gun shop.
- Story. Make sure the story mission based, and LIKE gta, maybe make the world decently large so you have a nice place to craft the game's universe.
- Enemies. Don't make the demons like this, improve their AI, don't make them OP af, and kind of improve them. Also, have different types of demons, maybe one that has low health but moves extremely fast, one that's slow but has a lot of health, one that can take possession of humans.
- Other Suggestions, You see, I have a cool idea for the phone. Maybe it can be used as a map, and can track everything whilst moving along the city. It can also be used as a menu, and maybe to do other things.
- Make the game a lot like gta, but also different. Implement and detail the game, add houses, add guns, and add a lot of customization, and make the game long.
- AI Another way to make the world better is to seriously improve the AI especially traffic AI, also the enemy AI.
- Verdict - If you take all my suggestions and do what you can you can make a pretty solid GTA Type game. 2.5 stars for now, maybe make another demo with more stuff, that might go up, hopefully your still alive/active and making the game.