First a short intro. I am new to the game development space and want to make some 2d games for iOS. I first come across cocos2d and kobold but then wanted something more graphical for rapid prototyping. I then found Game Maker which doesn't support iOS but is fairly easy to learn and then found Game Salad which supports iOS as well as other platforms. I know this question has been ask before but I want to know in terms of the types of games I want to develop what an learning investment path would be best.

The types of games genre I am interest are:

1. Side scrollers
2. Simple games like diamond dash or ninja fruits, shanghai, etc
3. Old fashioned zelda or dragonquest type (nintendo fan here:-) 2d adventure RPG games (real time or turn based)
4. Mystery turn based games like carmen sandiego, wizardry, myst etc.

So now the question becomes

1. Which game development environment should I invest my time in learning. Game Salad or cocos2d?

2. It would seem game salad would be great for quickies being graphical but in terms of 2d platform games etc would there be speed/performance/feature penalties?

3. Are there certain 2d games genre of the 4 above that Game salad is better at while certain type cocos2d would be better at?

Anyone with experience of both can share some pointers? Thanks. inexperienced jih